Adventures in Pentaxland

Featuring the Associated Lentil Soup™

Yours truly obtaining a DSLR was only a matter of time and finances. Dad had gotten himself a Pentax K-5, and since it generally did well and being able to share lenses would save some money, I ended up with a little K-x. I was subsequently bitten by the manual lens bug and developed a case of LBA (lens buying addiction), the results of which you'll be seeing here.

What you'll find on this page

Camera notes

Camera notes

Lens notes

Camera notes

Pentax K-5

Nice camera. Ours had a pretty bad case of front focus straight from the factory, but thankfully software adjustment took care of that. (Properly adjusted, AF accuracy actually is very good.) It still likes to overexpose a bit.

Pentax K-x

Looking out for something a little lighter than the K-5, I ended up with a used K-x and DA-L 18-55 kit. While AF required only minor adjustment, viewfinder diopter adjust seems quite a bit off and IMO does not even get close to its specified -2.5 dpt. I'll send it in for service soon. (EDIT: I never did, but maybe should since registration distance seems to be just a hair longer than specified, going by how many lenses have had trouble reaching true infinity focus.)
Otherwise I'm quite happy with the camera. The Pentax menu system is very user-friendly, exposure is pretty reliable (I have highlight extension on), and it takes the Eneloops that we still had from Dad's old Fuji S9600, though it be said that it likes to eat those for breakfast (f/w 1.02, <1.2 V per cell when it turns off) and I'm glad we have 3 sets. AF accuracy is good enough from about f/4 up – it's not a K-5. "It's not a K-5" also applies to the video mode's low-light abilities, but hey, the competition was no better in the day.

Chinon CP-7m

As far as cameras for film go, I'd only ever had ordinary compacts. The last one was a zoom/AF job, as standard by the mid-'90s. So having accumulated a bunch of manual K-mount lenses, I figured why not buy a matching SLR to play with? "Generic" K-mount SLRs from Ricoh and Chinon seemed to be competent but eternally underappreciated cameras. When the Chinon CP-7m came out in 1986, the first practical autofocus systems had just been introduced, and soon after they would take over the camera world.

Meanwhile, the CP-7m (a.k.a. Revueflex AC5) covered just about anything one could desire in a manual focus SLR. Uniquely, it allowed using non-A lenses in program mode, a feature necessitated by their lens lineup (generally good glass but not the latest technology). You'd also get an integrated winder that's good for 2.5 fps shooting in continous mode, and minimum shutter time was 1/2000s. It can use either a 2CR5 lithium battery or 4 AAs, which I like. Pushbutton operation and an integrated LCD were all the rage back then, so you'll bet it also has those. A flexible self timer? Check. Multiple exposure? Check. DX film sensitivity auto-detection with +/-2EV exposure compensation or manual setting from ISO 25 to 5000 in half-stop increments? Check. Bulb mode up to 90 minutes (!)? You bet. Split-screen focus indicator with microprism ring? Of course, in a MF camera. Only the lack of optical DOF preview seems like a bit of an odd omission.

The CP-7m I received (body only) fit the description of "battered workhorse" pretty well. Nicotine stench aside, it bears a fair number of scratches, and one of the strap holders is slightly bent as well. The contacts on the battery door showed some corrosion from previous battery leakage (nothing too bad though), and it appears that the goldcap used for microprocessor power backup upon battery removal is dead and barely holding a charge for a few seconds (not a totally uncommon occurrence, and Dad's far newer Fuji S9600 developed the same problem after just a few years). Quite surprisingly, I found a set of relatively new AA Eneloops inside (probably worth more than the entire camera), though they were entirely flat as the camera had been left on. (I doubt the seller even tested the thing in spite of a "100% functional" claim, given how it was on and giving a blank display even on photos.) Three of them turned out to recover and perform just fine, while one has high internal resistance (and probably did before; the first Eneloop cell with problems I've seen – these things are tough). Still, not too bad for a gift horse coming with a 1€-plus-shipping camera… ;)

With cleaned-up battery contacts and charged batteries, the camera sprang to life and turned out to be working fine, minus the aforementioned battery removal amnesia. Speaking of which, I'm not too fond of the battery door latch, which is kind of fussy.
At 625g including batteries (growing to 872g with the matching 50/1.4 lens), the CP-7m not the lightest piece of kit. It feels rather heavier than the K-x (which is similar on paper but more voluminous), aided by a different weight distribution and elongated shape that gives the lens more leverage when holding the camera one-handed, plus its edgy shape does not fit my hands too well to begin with.
The viewfinder image is huge, so in order to see the whole image and the indications at the side you have to press your nose against the camera back, which is a problem if your myopia means the -1 dpt of the viewfinder won't cut it by far. (They did sell optional diopter correction lenses back in the day; the -2 dpt one would have been right for me.) Brightness is decent with anything f/2.8 and faster that doesn't have too much transmission loss, which generally means zooms are much less fun than primes. Split-screen focusing seems to be OK but honestly AF confirm on the K-x strikes me as more precise (and even that won't cut it with fast lenses). If you get lucky, you have some fine repetitive pattern at the desired distance that'll generate moiré in the microprism ring.
Annoyingly, power off on the mode switch around the shutter release button is on the opposite side when compared to the K-x.

Porst compact reflex C-TL super (Cosina Hi-Lite 405 version)

Lens notes

Look what a bad case of LBA (Lens Buying Addiction) brought me.

DA L 18-55mm 1:3.5-5.6 AL

The lightweight "plastic fantastic" kit lens that I received with the K-x makes the (still inexpensive) 18-55 WR feel like a "proper" lens in comparison. Focus and zoom ring aren't really dampened and operating them makes some grinding gear noises heard. No lens hood included either, a generic JJC screw-on hood was used with mine. Yet, optically both lenses are the same. Good allrounders for normal use (non-rotating front lens included), with nice colors and contrast, though hardly the last word in sharpness at pixel level or speed. The digital kitchen scale rates this one at 201 grams, close enough to spec (200 grams) I say.

I have been appreciating the optical performance of the DA L 18-55 (/ AL II / AL WR) somewhat more after finding that unlike at 50mm (where tons of great primes exist that leave this one in the dust), a better replacement in the medium focal range (e.g. at 28mm) was not easily/cheaply obtained – let alone at the short end. Even at 35mm, where it arguably does best, it still fares well when compared to old primes – a Pentax-M 35mm 2.8 is a fair bit sharper in the center but that's about it. Its Achilles heel is the long end, as mentioned. It gets pretty slow at f/5.6, and even then still has plenty of spherical aberration haze wide open, with best results obtained around f/9.5-f/11.

I received a universal 52mm bayonet lens hood from Chinese maker JJC with this lens. While all plastic and rather inexpensive, it's a fairly well thought-out piece of kit. One piece attaches to the lens thread, with a counter ring for fixing it in the right position. The actual hood then is a standard bayonet affair, a little wiggly but OK. Things do come loose once in a while, otherwise it works well.
Since I can equally use this hood on other lenses (it's currently on the Rikenon P 50mm 1.7, below), I eventually obtained JJC's replacement for the PH-RBA bayonet hood that matches the DA L. It appears to be marginally lighter than an original part (17g vs. 23g for a PH-RBC) but fits perfectly, appears well-finished (with a roughened surface inside, which the cheaper generic part did not have) and is functionally equivalent at a fraction of the cost.

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RMC Tokina 75-150mm 1:3.8

An old (late-'70s, S/N 78xxxxx) manual one-touch telezoom with a "close focus" position. It actually predates the well-reputed Pentax M 75-150 f/4 lens (which apparently debuted in 1980). Fairly lightweight and compact – 428 grams, length 100 mm from mount, lens barrel diameter 55 mm, outer grip diameter 63 mm. 52mm filter thread. 11 elements in 9 groups. Rotating front element, as usual for an old zoom.

Mechanically it's quite lovely, all metal with nicely damped zoom and focus action (no zoom creep, and focus moves more lightly than zoom) and an aperture ring with the reassuring feel of a safe lock. Only full-stop aperture stops and no lens hood included (and as with many 3rd-party lenses including all my Tokinas and the Sigma, focus runs the other way compared to Pentax'), otherwise it would be perfect. The aperture itself is a 6-blade affair with rounded blades. Like similar Pentax lenses, longest focal length is reached with the focal/zoom grip closest to the camera.

Optically it's a bit of a mixed bag though. At the wide end, it's already usable wide open and sharpens up nicely in the center by f/5.6, the corners follow suit by f/8 to f/11. At the tele end things are rather fuzzy wide open, plus I'm not a fan of colorful bokeh. f/5.6 still isn't great. Optimum sharpness is reached by f/11, at which point it gets rather good. Not sure what's up with somewhat patchy sharpness still visible at f/8. Some CA at the tele end, any other aberrations eventually disappear when stopping down. The zoom range in between tends to be rather worse than the ends. Yesteryear's multicoating does not seem to be up to the standards of more modern lenses, since the lens exhibits rather noticeable ghosting when shooting into bright light sources, and contrast may be a little lower than with modern lenses, too. (Well, actually it's only partly multicoated, as was usual back then. The last element in particular is single-coated in amber, as with many other RMC series lenses, and that usually isn't the best match for the more reflective image sensors of DSLRs.) There also is a moderate amount of light loss, with more of a brownish / greenish cast compared to modern zooms.

Do not remove or loosen the three small flathead screws in the lens barrel unless you're prepared to readjust infinity focus. (Guess how I found out...) If you have already messed up, tighten just one of them and use focusing to move the lens assembly into the proper infinity position as confirmed by LiveView inspection. Then you can loosen the screw again and set focus to (a smidgen short of) infinity.
Note that while the lens was apparently supposed to be parfocal, the infinity focus point moves slightly when going from 75 to 150 on my sample, and adjustment would need to be performed at the less practical 75mm setting for infinity focus to be accessible across the range. You need to zoom out slightly in order to be able to reach the screws, hopefully without changing focus setting.

Trivia: I have nicknamed this lens "the hand grenade", though this term might be more fitting for the 135 2.8 (below) size wise.

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Rikenon P 50mm 1:1.7

A mid-late '80s manual prime lens originally intended for Ricoh's variation of the K-mount (K/R), usable like a K or M series lens on a Pentax unless modified. In spite of a "Ricoh pin" (of the less critical rounded variety) being present, I have not had any unusual difficulty mounting or unmounting this lens on my K-x, though it does turn less smoothly than others due to a rough surface that is likely to take its toll on the cameras's contacts in the long run. 52mm filter thread (yet again), non-rotating front lens. 6 elements / 5 groups (Ultron), as found in many 50/1.7s.

I have to say that I absolutely love this lens. It's among the sharpest I have, rivalled or exceeded only by other 50s so far, plus compact and fairly lightweight (148 grams), making it a nice "walkaround" lens for lighter cameras like the K-x.

Build of this Japan-made sample is (good quality) plastic with a metal mount, which is modest by the standard of the time but entirely adequate; the focusing ring is damped and turns smoothly. While aperture and DOF indications are melded in and thus quite well-protected, focus distance indications appear to be silkscreened only and may be subject to wear (people have noted this for the almost identical f/2 version).
It essentially was a better kit lens in the day, so you'll have to make do with a 6-blade (non-rounded) aperture and the somewhat less good bokeh this affords. A close focus limit of 0.6 m isn't anything special either; I like to borrow Dad's Raynox M-150 for macro work, which gives fairly nice results.

While I wouldn't normally want to use it full open (rather soft and with fringing), at f/2.8 it's entirely usable already, becomes very sharp at f/4 and really pin sharp at f/5.6, with this level of sharpness extending across the frame at f/8. It may have some more fringing and less contrast wide open when compared to the Pentax-M counterpart, but there's not terribly much in it. In return, the Rikenon P has better edge and corner sharpness at larger apertures (f/1.7, f/2.8), where the Pentax-M really falls off. This only evens out by f/5.6 or so.
I have not noticed ghosting and flares to be a significant problem, in fact image contrast generally is very good. The "shoot into a bright light source" test reveals a small greenish flare, not perfect but far from bad. The Pentax-M counterpart did better on this test, with no visible flares, but proved just about as susceptible to veiling flare. (Seems like the effectiveness of coatings depends on incident angle.)
This lens arguably is the very clearest I have, with virtually no greenish cast detectable.
Bokeh is so-so on this one. It's a tad busy-looking even wide open, and the edgy 6-blade aperture doesn't help one bit. It still easily smokes any of the zooms listed above though.

In short, for the moderate prices these Rikenons tend to be going for, they deserve a big thumbs up. (Recently one went for less than 20€, which I'd consider an absolute steal considering what it does. The f/2 version can go for under 10, which may be even more of a steal since it appears to be a slightly shrunk but not generally inferior construction with the same configuration of 6 elements in 5 groups – the competing Pentax-M 50mm f/2 is a 5-element affair. From what I've seen, bokeh isn't all that great, but sharpness appears to be fine. Unfortunately, however, the f/2 models seems to be merely single-coated, as basic lenses still commonly were around 1980. The bluish-magenta coating on the rear element still suggests decent practical results - I mean, I was quite happy with the 6/4 Porst Color Reflex Auto 50mm 1:1.7 (M42) despite its single coatings, even if having one less surface to contend with and a recessed front lens would be expected to help.)

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Sigma 70-300mm 1:4-5.6 DG OS

A modern-day telezoom lens for once. I was lucky enough to pick one up used at a very good price. This is about the biggest kind of lens I'd want to be using (without a tripod and on something like a K-x anyway), at over 600g and a significant length at the tele end. Both an AF motor and an optical stabilizer are included – the latter being handy for quietening down the viewfinder image and making the AF's job easier towards the long end, with the former not being awfully different from what's inside the camera. The optical formula includes a whopping 16 elements in 11 groups. The 62mm filter thread is not exactly tiny either.

Build is plastic with a metal mount and rubberized zoom grip and generally gives the impression of getting the job done without being flimsy or wobbly. A rough sparkly ("crinkle"?) finish is most prominent on the included lens hood, which smudges fairly easily. There is no zoom creep worth speaking off, though some focus creep is noted in MF mode (but none in AF). When reversed for storage, the lens hood covers up the focus ring, so putting it on or taking it off like that requires rotating focus to one of its stops, which is mildly annoying. The stabilizer always draws power even when turned off (presumably the moving elements are just held in center position then), increasing battery drain.

So, is a modern-day zoom worth it when it comes to image quality? I'd say yes, it is. This Sigma is not as woefully soft wide open as my film-era lenses can be (e.g. the Tokina 75-150 @150 or the 135). Even when it's only doing an average job on sharpness, like at 75 mm, it's still up to the Tokina at center and falling off towards the edges. When it's doing well, center sharpness easily outruns any of my film era lenses (save for the Rikenon P, possibly). And of course, modern-day comfort features are available.
Only color rendition is something that you may not appreciate that much, as it gives a bit of that oldschool greenish tint and in particular loses more blues in the sky than I'd like. Oddly enough, looking through the Sigma at a white wall only shows a rather moderate brownish cast. In fact, I bet it's doing better than some of my primes there. It's about on Pentax-M 80-200/4.5 level while having more optical surfaces, and thus better than any of my other old zooms. DxOMark reckons it's hovering around 0.3 stops of transmission loss, which does seem about right.

Bokeh is rarely a criterion for a telezoom like this, and so it shouldn't be surprising that it is a little on the busy side, even wide open, with the double contours you'd expect towards the back. Still, it's not too bad either.

I did a landscape shot at 135mm f/8, comparing it to the AGFA/Chinon 135mm 1:2.8, which is an OK but not exactly exciting prime of yesteryear. In the center, fine structures clearly were better defined in the Sigma, with less bloom around highlights, and sharpness across the frame proved about equivalent (weak bottom left edge on the Sigma vs. weak bottom right edge on the Chinon). That's progress for you. Only color rendition proved better on the prime, with blues being much better represented. It's noticeably brighter, too. All the glass inside the Sigma appears to be taking its toll there. (I think the Chinon only is a 4 element / 4 group affair, making it far less critical even with yesteryear's coatings. Looking at a white wall, it shows very little greenish cast at best and is up with the best of my primes.)

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RMC Tokina 135mm 1:2.8

A late-'70s/early-'80s (S/N 82xxxxx) manual tele prime with an integrated lens hood. A 5-element / 4-group affair, it will seem. 6-blade (rounded) aperture. 52mm filter thread, quite heavy at 405 grams (most lenses of similar specs tend to be a little under 400 or even lighter). Length from mount is 75 mm at infinity, lens barrel diameter is 57 mm, grip diameter is about 63.5 mm – quite compact for a lens like this.

As with the older 75-150, build quality is impeccable and qualifies as bulletproof, while optics are only so-so. Focusing and aperture ring move smoothly and precisely. Like other RMC Tokina primes of similar vintage (and similar to Pentax M series ones), it features a decorative chrome ring on the lens barrel. A lens hood is integrated, which partly disappears under the focusing ring when not in use.

Sharpness basically is already there wide open (it's not easy to evaluate in a MF lens like this, as you easily misfocus), but the image turns out rather flat due to lots of haze. The haze is mostly gone by f/4. Things never really get an awful lot sharper, staying in decent but ultimately average terrain. Purple fringing, of which there is quite a bit wide open, is reduced when stopping down. (PF levels at f/8 are similar in this lens and the DA L 18-55.)
A near focus limit of 1.5m is rather pedestrian but apparently typical of mid/late 1970s 135s.
At least the coatings seem somewhat better than on the 75-150, though contrast doesn't strike me as particularly impressive. (This one has a big, bulbous, exposed front lens. The integrated hood keeps a good bit of stray light off but some does remain. Apparently blackening inside the lens barrel does not perform as well as it should, as I found the Chinon counterpart to edge this one out. Besides, the last element is only single-coated in amber, which has been found to be somewhat problematic on DSLRs with their more reflective sensors.) Looking at a white wall, the greenish cast imposed is significantly reduced when compared to the zoom with its far greater number of optical surfaces, in fact this lens looks barely any worse than the Chinon counterpart and still ranks among my most transparent.
f/2.8 wide open does give a nice and bright viewfinder image, and bokeh is nice and smooth both in the front and in the back, so it should make a decent portrait tele.

This lens left me unconvinced. Bokeh is fairly good, I'll give it that. Later I got a similar AGFA-branded Chinon, and what do you know, optical performance turned out to be rather similar in general with only moderate differences (better-controlled aberrations on the Tokina vs. better contrast, better sharpness and somewhat better rendering of blues on the Chinon). So it seems like this is how run of the mill 135/2.8s of the time around 1980 perform. Reviews even indicate that while the newer Pentax-A 135 2.8 and the accompanying Takumar Bayonet 135 2.8 do better wide open, for somethings heads and shoulders above this lens I'd have to obtain an F 135 2.8 – and ultimate sharpness still wouldn't be near a decent 50mm. (For a really great 135, it seems I'd have to go M42 and grab a Zeiss or somesuch.) A rather sobering prospect. I should do a comparison with the 75-150 zoom – I wouldn't be surprised if that one turned out to be at least equally sharp at f/8 (though I can see the prime ahead at f/4).

I do have reason to believe that the lens had a bit of a bumpy ride, as it turned up floating loose in a box together with a teleconverter and essentially no padding. There is no sign of any substantial damage though, only the snap-on lens hood seemed to have taken a bit of an impact and needed some convincing to come off. Focusing extends just a little past infinity, and there is no rattle or any other indication of damage. I'd say it hardly saw any use in its previous life, there is nary a dust speck inside.

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Pentax-M 80-200mm 1:4.5

After all the third-party film era manual lenses, here's an original Pentax M series model. This is the far more common first version, as evidenced by 562 grams on the kitchen scale (555g official). Mine was obtained cheaply and is thoroughly banged up, with a dent in the hood (and slight dent in the 52mm filter thread) and numerous scratches and signs of wear, including a missing white plastic bump (not sure what this one is good for anyway – seems like you can line it up with the lens release lever / button when changing lenses in dim light, or that's what Google told me anyway). Nonetheless, it seems to be in fine shape optically.

The lens still working fine speaks volumes about its robustness. Yet it's not perfect mechanically. My sample has bad zoom creep, which is moderately annoying, especially since focusing subjectively requires more force than zooming on this one-touch construction! (I peeled back the rubber grip at both ends but did not find any screws there, so it seems to differ from the newer A 70-210 in this regard.) The integrated lens hood, while a nice touch, seems rather short for something with a maximum 200mm focal length. Aperture ring operation is reassuring but not the last word in smoothness. I do appreciate the half-stop steps a whole lot, however.

At the wide end, results are already usable wide open, things get better one stop down, and sharpness peaks around f/9.5. Peak sharpness isn't the highest I've ever seen but still rather good for an old film-era zoom. The tele end starts out fairly usable wide open, though you'll want to stop down by half a stop to get rid of the fringing. Sharpness peaks in the f/9.5-f/11 vicinity, on a decent if not awe-inspiring level (the modern-day Sigma 70-300 DG OS is quite a bit sharper at this focal length, you've got to notice progress somewhere after all).

Contrast seems decent, as you might expect on a Pentax SMC lens. It also imposes less of a greenish cast than my other old zooms, though it's no better than the modern-day Sigma 70-300 DG OS (progress of 3 decades has to show up somewhere, right?). It still manages to edge out the odd prime of similar vintage.

As you'd expect on a zoom lens, bokeh is rather on the busy side. It's still halfway decent, but nothing great either.

Overall, this Pentax lens shows the traits of a good construction. Most of all, rather little stopping down is required to get decent results, and aberrations seem well-controlled. It is showing its age when it comes to maximum sharpness reached (rather typical for an M series lens, in fact).

So if you see a thoroughly worn lens, it might well be because it's a good performer. A very well-kept sample may have had a very caring owner, or it just spent most of its life on the shelf, maybe because it wasn't all that good.

I later obtained a second sample in better cosmetic condition and with less zoom creep, but that one will not stop down beyond about f/16. Ultimately I find I'm just not using manual zooms an awful lot – keeping track of focal length (for optimum sensor SR) is too cumbersome.

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Tokina AT-X 28-85mm 1:3.5-4.5 (older version)

Oh no, yet another Tokina lens. This medium-range manual zoom was available in two rather different versions in the early and mid/late 1980s; I apparently have the older version (S/N 830xxxx). This apparently was a fairly advanced lens in its day, using 15 elements in 10 groups if I'm informed correctly (though the depiction on the box clearly shows 14 elements in 9 groups). 62mm filter thread, rotating front lens.

If you expected an upscale Tokina lens to be well-built, you'd be absolutely right. It's the kind of full metal construction you've come to expect from their older offerings (engraved lettering included), if maybe not executed with the same degree of perfection. The entire lens weighs in at a respectable 492 grams, plus an extra 37 grams for the included slide-on metal lens hood, making it a noticeably hefty affair on something like a K-x. The focus ring with its nice and wide rubberized grip moves smoothly and rather lightly – maybe a little too lightly even. The zoom ring makes some gear noises heard, and the aperture ring is comparable to the Pentax 80-200 in that it moves precisely if somewhat roughly. Half-stop aperture steps are available between f/5.6 and f/16, which I appreciate, but at wideangle the jump from f/3.5 to f/5.6 is rather large. The aperture itself is a rounded 6-blade affair, consistent with other Tokina lenses of mine. A close focus range is accessible by pressing a button and rotating zoom beyond the 85mm position.

Zooms with parabolic extension as you move across the zoom range (i.e. shortest somewhere in the middle) seem to perform best where they are shortest. That is the case in the 50 to 70 mm range for this lens. At 85 it's about as long as at 40, and significant extension is reached at 28. I found that 85 isn't half-bad even wide open, a bit of purple fringing and a tad "dreamy" but rather usable in terms of sharpness already. Things improve when stopping down, with a good level of sharpness at f/8 and optimum reached at about f/9.5 to f/11. 50 also is very usable wide open and gets really sharp as you stop down, reaching Rikenon P 50mm 1.7 level across the frame by f/8 (no mean feat for a zoom), minus a bit of CA near the edges. Quite impressive.
28, by contrast, is rather weak. While things are very sharp in the center even wide open, they just get softer and softer as you move towards the corners, with quite a bit of CA to go along. It's somewhat "dreamy" at this point, too. This focal length also exposes an apparent alignment problem of my lens, as the left edge is particularly bad. This sample does not appear to have been abused, so I guess it came like that right from the factory. 35 is better overall (if not as good in terms of center sharpness) but still shows a bit of CA and somewhat soft edges.
As others have noted, the lens is a tad weak on blues, giving a bit of an oldschool greenish/yellow cast. In fact, looking through it at a white wall, I'd have to award it the title of "king of green" among all my lenses. All those surfaces in there would seem to be stretching the limits of the coatings available to Tokina at the time, or maybe it's all that glass.
Unsurprisingly for a zoom, I didn't find bokeh to be all that great. Actually the background tends to be smoothed nicely but the foreground can have some pretty annoying double contours (apparently enough to false-trigger the AF at times).
Sensitivity to flare seems to be OK considering how large the front lens is. A longer (possibly extensible) hood probably isn't a bad idea when using it on crop DSLRs. I cannot provoke much in terms of ghosts when shooting into a bright light source, so coatings seem to be good.
I'd estimate minimum focus distance in close focus mode to be about 0.4m or thereabouts, which at 85mm is rather useful. Results wide open are a little soft still, but f/5.6 works well. Slight tendency to backfocus on my sample, maybe 2..4 mm at minimum focus distance. Bokeh is definitely less annoying than the busy colored one on the old 75-150, but gives fairly heavy double contours in the front (enough to false-trigger the AF at times). Seems to work well with the Raynox M-150.
The focal plane seems a little oddly shaped on my sample, possibly accounting for the alignment issues observed. People have noted that this lens appears to produce less DOF than you'd expect for a given f-stop, indicating an aperture that's geometrically larger to compensate for transmission loss, and indeed focusing seems unusually critical, with AF confirmation being rather less verbose than on some other lenses (but that might also be a result of shorter focal length). Results in the field have been a little odd at times.

Investigating the "geometrically larger aperture" claim, I did find a difference of about half a stop, i.e. I had to set f/9.5 for an aperture that looked about as big as f/8 on either my Rikenon P 50/1.7 or Porst Auto 50/1.7 (actually maybe a hair smaller, but that was the closest I could get), same for f/6.3 vs. f/5.6. This sort of difference isn't huge but noticeable in terms of blurring.
Even at nominally the same aperture, however, the AT-X 28-85 actually produces slightly darker images, so its transmission loss must exceed the Rikenon P's by more than half a stop (maybe 0.6 stops or so). (The Rikenon P is among the very clearest of my lenses, so I'd be surprised if it lost a lot more than 0.1 stops.) As an aside, AWB on the K-x failed to fully eliminate its greenish cast on my 6500K, CRI 80-something fluorescent lit white wall, regardless of how the tungsten light option was set, though it did get better (not perfect) when cranking up exposure times by 1.5…2 EV vs. whatever green button metering suggested. Seems like the "scene" looked rather greenish to begin with, and AWB apparently is reluctant to apply heavy corrections. A daylight outdoor shot again did not eliminate the greenish tint altogether, although it was greatly reduced, and the Rikenon P gave a bluish cast like several other lenses of mine have (not real, just an AWB artifact), so it seems that AWB may be tweaked for lenses of average transmission.

Overall, this is a rather competent (if occasionally finicky) old zoom lens, probably best used in the 40..85 mm range. Well-built, as usual for a Tokina. I do wish mine didn't have a slight alignment problem, but at least I got it for chips in otherwise good condition. A little on the heavy side for my tastes. (The preceding RMC 28-85/4, while reputed to be better optically, apparently is even bigger and heavier. Ouch.) Oh, and I hope you like green…

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XR Rikenon 50mm 1:1.4

Anyone interested in manual focus lenses is likely to end up with a number of 50mm primes, simply because they are so plentiful (read: inexpensive) and so many of them are good. Looks like I'm no different, since I just acquired an XR Rikenon 50mm 1:1.4. Unlike the newer Rikenon P 50mm 1:1.7, this early/mid-'80s Ricoh lens does not feature a P aperture setting and corresponding "Ricoh pin", though I can't claim that putting the lens on or taking it off would feel all that different.

Now as you've no doubt read, the P 50mm 1.7 is a lens that I've been enjoying an awful lot on my K-x – compact and lightweight yet built perfectly fine, coupled with terrific image quality (MOR bokeh excepted). This one upgrades it with almost-all-metal construction, one more aperture step at f/2 (the P 50mm 1.7 had clicks at 1.7 and 2.8, which is quite the jump), an 8-blade (rather than 6-blade) aperture and a shorter minimum focus distance. (Actually you lose the ~f/22 setting that the P position affords, but that's a general P vs. XR thing.) 52mm filter thread, non-rotating front lens, mount surface and straight aperture blades are unchanged. Coatings also look the same (i.e. a mix of multi- and single-coating, with perhaps a higher percentage of single-coated elements), though with a larger front element I'd expect that some more attention to flare may be needed. The last element is pretty huge, I'd say it's just as large as the front lens in diameter. It also slides in and out "naked", making it relatively easy for dust and things to get into the lens assembly.

Substantial build quality (engraved lettering included) and larger lens elements reflect in substantial weight – 269 grams is quite heavy for something just a little longer than the P 1.7 model (which my kitchen scale rated at a mere 148g, and it doesn't feel flimsy in the least). The aperture ring operates with a moderately light yet precise feel, which is lovely, and focusing is as nicely damped as on the 1.7 model, with a whopping 180 degree focus throw (vs. about 120 degrees, though it appears that the extra 60 merely accomodate for the extra minimum focus distance).

Preliminary tests of image quality indicate that, not unexpectedly, this one appears to be another winner. While f/1.4 looks "dreamy" even at substantially reduced size, with all the fringing and colored bokeh one could want, this largely clears up by f/2, which I'd already consider usable. f/2.8 is nice and sharp in the center, though the corners aren't there yet. They improve on stopping down further. Bokeh remains a little more busy than the very best, and while the 8-blade aperture should make for more inconspicuous highlights, it does produce plainly visible octagons.

Vignetting is quite noticeable wide open, but irrelevant by f/2.

A quick comparison showed that this lens does not achieve the same edge-to-edge sharpness exhibited by the nominally lesser P 1.7. It's plenty sharp in the center but even at f/8 still drops off a little towards the edges. (Incidentally, the same characteristic is to be observed on the respective Pentax M series 50s, and Zeiss lenses are not excepted either.) So I guess they'll both have their uses for me.

In macro use in particular, astigmatism towards the corners is quite pronounced.

This lens appears to have been opened at some point, as there is a small scratch on one of the inner elements. Fortunately this should be entirely irrelevant past f/2 or so.

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SMC Pentax-M 28mm 1:3.5

The less common of the two 28mm M series lenses, the 3.5 enjoys a reputation for better contrast then its 2.8 sibling and "that 3D quality". Mine arrived somewhat worn and a bit dirty, but it cleaned up well. Not really a bargain this time. 49mm filter thread, still among my most compact 28s. Lens configuration is 6 elements in 6 groups. S/N 66xxxxx.

Build is all metal (save for the usual rubber focus grip), reflecting in a weight of 179 grams in a lens a little longer but slimmer than the (plastic) Rikenon P 50mm 1.7. The aperture ring is stepped at half f-stops, except between f/16 and f/22. (Not sure what the position between f/3.5 and f/5.6 would be exactly, around f/4.5 I guess.) Focus distance markings are visible in a cutout, as with many Pentax primes since the mid-1960s. Focus goes from 0.3m to infinity in a mere 90 degrees, reflecting the wider DOF of a relatively slow wideangle lens. In stark contrast to the XR Rikenon 50mm 1.4, the last element is pretty tiny, smaller than on any other lens I have – then again, it's the first 28, and f/3.5 isn't too fast either.

The lens gives a usable degree of sharpness wide open, with mere hints of fringing and minimal vignetting at best (on APS-C) – an indication of a good construction. Things sharpen up thereafter, with center sharpness reaching its optimum at about f/8-f/11, with f/11 improving edge/corner performance further. The right-hand side is weaker on this sample and can get rather soft indeed. (It appears that some interesting field curvature is at fault here, with the focal plane moving closer towards the edges.) Contrast appears to be nice, and there is just a bit of CA. For some reason, the lens seemed to throw off auto WB on the K-x, resulting in a heavy purple cast in a nicely lit daytime outdoor test scene (and no, the lens was shaded, so no flare). Then again, other lenses have also done that.

Sounds good so far, no? Problem is, I can get about the same level of performance out of the lowly DA-L 18-55 kit lens (with lens correction on), with no AWB problems and more flexibility and comfort to boot. Sure, that one is larger and a bit heavier, but it's not large and heavy in absolute terms. Not sure whether I'll keep this 28. If that already is one of the better lenses when it comes to old MF 28s (and judging from the 28/2.8s that I've picked up so far, it actually is), things aren't looking too good for my bargain-hunting self. Guess I'll have to shell out for a modern-day lens in this range eventually.

In the "look though it at a white wall" test, the seems to have the least greenish cast among my 28s, though the Porst 28/2.8 auto F is about equal and the 18-55 kit is not far behind. The AGFA/Chinon 28/2.8 trails behind, ending up about on par with the Vivitar K03 counterpart (and the M 80-200/4.5, which does well for a zoom of its time).

This lens enjoys a reputation for being optimized for intermediate distances. Sure enough, mine does a good job shooting a test chart at about 1 m, but closer to infinity doesn't do better than the kit lens. Actually it doesn't even quite reach infinity on my K-x (or 50 m, for that matter), which certainly doesn't help. Maybe they had issues with performance near minimum focus distance and decided to tweak the lens for some kind of intermediate distance. Plus, it typically doesn't hurt when things look good in test chart shooting (i.e. magazine reviews).

I am under the impression that M series lenses were designed to give then-usual performance (plus SMC coating) in a more compact and lightweight formfactor. Somewhat lower peak sharpness wouldn't have mattered much on film anyway, and a number of K series lenses remained available for the discerning shooter. With modern high-resolution DSLRs, this tradeoff now becomes plainly visible. That said, they're usually fine lenses for their time.

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Auto Revuenon MC 50mm 1:1.4 (6-blade aperture)

Revuenon lenses of all kinds are common in Germany, as Revue was the house brand of a large mailorder outfit. This particular one shipped as a kit lens for 1980's Revueflex AC-2, a rebadged Chinon CE-4. It can therefore be assumed to be equivalent to the corresponding Auto Chinon, save for a different style rubber grip and orange rather than green focus distance indicator. (You'll also see an AGFA branded version once in a while, which paradoxically seems to fetch higher prices – collectors?) Note that there actually are two lenses that were sold under this name; the other one was available separately (hence is correspondingly less common) and featured an 8-blade aperture (rather than the 6-blade variety in this one). Both appear to be using a 7 element / 6 group configuration as common in 50/1.4s.

On with the "lowly kit lens". Mechanically, it's a nicely built metal affair (rubber focus grip) with engraved lettering. (There's some plastic to be seen around the rear element, just like on the XR Rikenon.) It weighs in at 247 grams on the kitchen scale (somewhat lighter than the Ricoh counterpart) and features a 49mm filter thread. You get a 6-blade (rounded) aperture, similar to what the Tokina 135 2.8 had. The aperture ring covers f/1.4 to f/22 and is stepped in half stops between f/2 and f/16. Focus runs between 0.45m and infinity in an estimated 200-210° turn, with decent smoothness. (It turns in the same direction as all my Pentax and Ricoh lenses, unlike all my Tokinas.) The last element is bigger than on the Rikenon P 1.7 but not as big as on the XR Rikenon 1.4. My sample proved nice and clean, with only a bit of external wear.

Optically this lens behaves somewhat like the XR Rikenon. Wide open there is severe "dreaminess" (spherical aberration) going on, even though basic sharpness already appears good at this point – in fact, it seems to edge out both of my Rikenons as far as you can tell through all the haze. (It also seems to focus a tiny bit further out to infinity, while both Rikenons may be just a hair short. Fast lenses, modern DSLRs and accumulated tolerances are good for all kinds of fun...) Things significantly improve at f/2, and f/2.8 should be usable all-round. I was impressed by center sharpness even at this point. Edges and corners lag behind and gradually sharpen up when stopping down. They still aren't totally perfect at f/8, much like with the XR Rikenon. (Astigmatism appears to be better-controlled than in the Ricoh lens though.) Interestingly, center sharpness already begins to degrade at this point, as also noted in this review of the Auto Chinon counterpart.
It seems that spherical aberration is noticeably better controlled at f/2 when compared to the XR Rikenon counterpart, where it may have been deliberately undercorrected to give nicer background bokeh. The Pentax-M and Rikenon P 50/1.7s still are a little better-behaved at this point though.

At first glance, lens coating looks like a standard MC affair similar to my RMC Tokinas or this lens's little brother, the 50/1.9 (while my 50mm Rikenons feature a brownish front lens coating, as do the Auto Revuenon MC 50/1.7 – which interestingly seems to belong to the same "family" – and 50/1.8 – which is a different beast altogether – models). However, there is a greenish reflection on the front lens that reminded me of some 55/1.2s... the Porst Color Reflex MC Auto in particular, apparently Cosina-built. What this means for the production of our 50/1.4 is anyone's guess.
Flare sensitivity turns out to be decent, about on the level of my 50/1.7s but not as good as the XR Rikenon, which proved to resist flare rather well. Use a lens hood, and you should be fine. Compared to my 50/1.7s, contrast seems a little softer, with colors possibly being a hint warmer, too. In fact, looking through it at a white wall betrays a fairly noticeable brownish cast. Not as bad as the Tokina AT-X 28-85, but worse than the Pentax-M 80-200/4.5 zoom. The XR Rikenon fared much better, ending up about on par with my average 50/1.7s (Pentax-M and Porst Auto M42) in this test.

Bokeh looks more or less like it does on my Rikenons... I have yet to test highlights though, which would be expected to be more well-behaved than on e.g. the Rikenon P 50 1.7 due to a friendlier aperture shape.

Aperture calibration may not be the very most accurate on my sample, as stop-down metering indicates some deviations from expected exposure times. Besides, I found out that the K-x will not go any faster when increasing aperture from f/2 to f/1.4, and that's on both of my f/1.4 lenses.

There is some vignetting wide open, but less than on the XR Rikenon, which shows quite a bit. It's a non-issue by f/2 for both.

The Raynox M-150 macro lens holder won't fit a 49mm thread… oops.

Looks like we have another competent performer here. Only coatings do not seem to be quite as good as on my other 50s.

It seems to be an unwritten rule of LBA that you end up with more 50s than you really need, while finding a good 28 is a lot more tricky.

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Porst 28mm 1:2.8 MC auto F

Photo Porst used to be a big camera retailer in Germany, and for a long time they also sold cameras and lenses of their own at attractive price points. Standard mass-market stuff, and around 1980 usually Japanese-sourced and average to decent. (You'll find many Cosinas, but also Chinons, East German Prakticas and Fujicas, with a corresponding array of M42, PK and Fujica-X lenses.) This particular PK mount lens has an impressively large front element, as indicated by a 58mm filter thread, and judging by a 79xxxx serial number, dates from the late '70s. The closest equivalent I could find was a Soligor 28/2.8 (S/N 479xxxx range), presumed to have been manufactured by Sun Optical. This lens must have been fairly short-lived but was obviously produced in significant numbers. (As the lens design appears to be more similar to some early/mid-'70s models, possibly something was "recycled" with multicoated elements here.) The designation "F" apparently may indicate a 6-element job in who knows how many groups (their 135/2.8s are marked "auto D" and are standard 4/4 affairs).

Mechanically we're looking at yet another solid and all metal affair, reflecting in a weight of 273 grams. In spite of being as big as it is, the front element actually does not rotate. Focus runs nice and smoothly over a whopping 270° turn (if in the opposite direction compared to a Pentax lens), with a minimum distance of 0.35m. You get a 6-blade aperture (not rounded, but at least better than the 5-blade affairs you'll find in a number of 28s), and the aperture ring runs from f/2.8 to f/22, with half-stop clicks between f/4 and f/16. Setting the aperture sounds a little rattly (also adding to shutter noise), but that's about the only complaint there. Coatings appear to be the usual 3rd-party manufacturer fare of the time (similar to my RMC Tokinas).

This is the first of my lenses to use a simple push-on front lid. It's not exciting, but gets the job done.

Optical performance is, well, decent but unremarkable. Things are fairly "dreamy" wide open, so you'll want to stop down to f/4. At f/8, there's not much of a difference in center resolution to the Pentax-M 28 3.5. Corners are even softer. There is some CA, too (thankfully, it's easily corrected when shooting RAW). A bit surprising given all that glass, but consistent with the manufacturer's track record. Colors/contrast are decent but not quite up to Pentax standards either (blues in particular are a bit more subdued – though when inspecting lenses by eye, there isn't much in it when it comes to greenish/yellow cast, and both are doing well).

Big hunk o' glass gets beaten by a little Pentax lens, oh well. At least it usually goes for a fraction of the price, too. (Well, now that I have a few more 28s, I can say that this easily is the worst of the bunch when it comes to off-center sharpness and CA. This also points towards an old design.)

I noticed that when you look inside the lens from the front, you can plainly see the "walls" inside. I don't think that bodes too well for flare resistance. The Pentax-M 28 3.5, by contrast, looks pitch black around the lenses, and there isn't much too be seen in the lowly DA L kit zoom either. A case for "Pimp my Porst"? ;) (One could consider covering part of the excess diameter of the front lens, too. Maybe that gives better performance on APS-C.)

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Vivitar 28mm 1:2.8 MC (K03)

I recently acquired another 28/2.8, the reasonably common Komine-built Vivitar referred to as K03. It arrived in fine condition with only a little wear. This was my first lens to show appreciable play in the lens barrel and focusing ring though. It's just a bit longer than the Pentax-M 28/3.5 (but bigger in diameter); weight also is similar at 186 grams. Looking inside, lens configuration appears to be 7 elements in 7 groups.

Mechanically this is your average manual prime lens. Metal outside with a rubber focus grip, though it does seem that plastic is used inside the lens barrel. Focusing starts a little short of 0.3 m and extends a bit past infinity, covered by turning the focus ring about 170°. The aperture can be set from f/2.8 to f/16, with half-stop clicks throughout. (It would have been nice to see f/22, which tends to come in handy for flash use once in a while.) It is a 6-blade (rounded) affair, which is nice for a 28.

Looking in through the front lens, we see decent multicoating (not SMC level, obviously), and internal blackening that appears to be incomplete, ending up somewhere between Porst 28/2.8 and Pentax-M 28/3.5.

First optical tests indicate that the lens is best stopped down to at least f/4, at which point "dreaminess" and fringing (both being heavily present wide open) are pretty much gone and it already delivers a rather decent level of sharpness across most of the (APS-C) frame. It never really gets pin-sharp the way my 50s do, but is quite even by f/11. Performance reminds me of the Pentax-M 28 3.5 in two regards: Field curvature appears to be similar (focus moves closer when approaching the edges), and the right-hand side is a little worse, also exposing CA more readily (which is not extreme but visible).

Looking through the lens, it imposes somewhat more of a greenish / yellowish hue than the Pentax and Porst 28s, about on par with the AGFA/Chinon below.

All in all, this would seem to be among the weakest of my 28s.

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AGFA COLOR (Chinon) 28mm 1:2.8 Multicoated

Yes, yet another 28/2.8, my third to date. This one is another Chinon OEM job, much like the Auto Revuenon 50/1.4 was, and it sports the same style focus ribber grip, with a more standard green-colored rather than orange focus distance indicator this time. (You probably won't be surprised to read that an Auto Revuenon version also exists, but be careful since a Cosina-built one with a 52mm filter thread appears to be at least equally common.) It's slightly longer than the Vivitar K03 counterpart and noticeably longer than the Pentax-M 28mm 3.5, but not as big as the huge Porst. It weighs in at 211 grams, heavier than both the Pentax and the Vivitar. 49mm filter thread. Lens configuration appears to be 7 elements in 7 groups, but decidedly different from the Vivitar (longer and with a bulbous front lens).

Build-wise, this one is your standard ca. 1980 prime, mostly metal and a bit of plastic plus a rubber grip on the focus ring. Focus moves smoothly from a little under 0.3m to infinity in about 160° – thankfully in the same direction as on a Pentax lens, as usual for Chinon. The 6-blade (rounded) aperture can be set from f/2.8 to f/22 with full-stop clicks only. (The iris looks a little funky between f/2.8 and f/4 anyway.) The front element isn't unusually big but rather bulbous, which is why it also is slightly recessed. Blackening inside looks to be decent.

Having three 28/2.8s at my disposal, I thought why not compare them wide open? A quick shot proved interesting. First, the Vivitar K03 – drenched in blue glow. Then, the big Porst – also very dreamy, but the haze is not as annoyingly blue at least, so that one might be usable as a "soft focus" lens. Finally, the Chinon – some haze and fringing, but of a much reduced magnitude compared to the other two, yielding a shot I'd consider usable if a little soft still.

Looking at other apertures, sharpness strikes me as decent but not exceptional, much like my other 28s. (If I want pin-sharp, it looks like I'll have to stick to 50s.) There's a bit of CA, not too bad though. Only when looking at controlled test shots did I realize that the right-hand side is pretty phenomenal and nice and sharp even wide open, while towards the left edge it gets pretty awful with blurriness and a good bit of spherical aberration. Such a tease! Decentering? Vignetting, which is visible wide open, is gone by f/4.

A quick landscape comparison shot at f/8 vs. the DA L 18-55 kit lens at f/9.5 didn't produce a clear winner. Colors and contrast are about the same, maybe just a hair more greenish on the Chinon, which also proves noticeably darker. The Chinon might also be a little less sharp when moving away from the center, but then again it was half a stop further open. Overall, there really is very little in it.

The somewhat stronger greenish cast was confirmed in looking at a white wall through both lenses. The Chinon is about on par with the Vivitar K03 here, which in turn about equals the Auto Revuenon 50/1.4 (which wasn't too exciting for a 50 in this test).

At f/4, the Chinon is sharper in the center, but the outer regions suffer a lot more than on the kit lens, assuming the latter is focused correctly.

I took a shot including the sinking sun at the very edge with both lenses, and honestly I'd have a hard time telling which is which if nobody told me. Using a flashlight, I can generate veiling flare with both about equally, though arguably the 18-55's more whitish haze isn't quite as annoying as the standard purple haze on the Chinon. Boooring. As usual, a hood will keep off a good bit of stray light.

Overall, a rather competent performer as far as old 28s go, arguably among the two best of mine. You may even dare to use it wide open, gaining about a full stop over the 18-55 kit lens when needed. Too bad its performance is so uneven across the field.

I obtained a JJC clone of the Pentax PH-SA49 clip-on lens hood. Aside from the plastic being rather thin and the mechanism apparently manufactured on a bad tolerance day, it fits all of my 49mm lenses (AGFA / Chinon 28/2.8, Auto Revuenon / Chinon 50/1.4, Pentax-M 28/3.5), both normally and in reverse. It does not cause any vignetting even when mounted at a 45° angle on a 28mm (on APS-C). When reverse mounted, you can in theory attach a lens cap, but it would have to be smaller than 49mm (maybe 47.5 or so, as my calipers show an inner diameter a little short of 47). So it works and it was cheap, but I don't think I'd buy another one.
Basically the same goes for a HAMA clip-on rubber hood, which, while more solidly made in generally, showed some excess glue and does not even attempt to provide a filter thread or mount in reverse. Judging from the packaging, I bet this one spent the last 20 to 25 years on the shelf.

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AGFA COLOR (Chinon) 135mm 1:2.8 Multicoated

Here's another Chinon lens, another AGFA branded one (actually obtained from the same source as the 28/2.8). It may sound stupid, but I like the looks of these Chinons. The 135/2.8 is reputed to be only moderately exciting, but after I wasn't too happy with the Tokina and an Auto Revuenon version of this lens did decently in a review of various 135s, I decided to try one. It actually is quite similar to the Tokina, including a 52mm filter thread, an integrated lens hood and a 1.5m minimum focus distance. Likewise, the lens configuration appears to be very similar in the first three elements, though the Chinon has one larger last element where the Tokina has two smaller cemented ones, and coatings differ. The distance from first element to mount is just about identical for both, the Chinon merely has a marginally longer lens barrel (77.5 mm at infinity vs. 75 mm, 57 mm diameter for both; grip diameter is about 63.5 mm for both).

Mechanically our Chinon appears solid if a little less fancy than the Tokina. It lacks the chrome trim on the lens barrel, and the sliding lens hood does not partly disappear under the focusing ring, effectively giving a slightly smaller effective length when in use (in spite of a longer lens barrel). At 392 grams, it also is a bit lighter. As usual for Chinon lenses (but unlike Tokina, Cosina and other 3rd-party makers), focusing turns "the Pentax way". It does so basically smoothly even if something in the aperture mechanism seems to rub on a moving part when wide open, making not-so-pretty noises near infinity then. As on the 28/2.8 and the Tokina counterpart, the aperture ring clicks in at full stops between f/2.8 and f/22.

Optical testing proved one point in particular: When optimum sharpness is desired, accurate focusing becomes very difficult with a 135mm lens, even when using LiveView. Most of the differences between this lens and its Tokina counterpart were found to be caused by variations in focusing. Both show a good bit of "dreamy" haze wide open and need to be stopped down to f/4. Sharpness at f/8 appears to be very similar – decent but nothing that couldn't also be reached by a modern middle-class telezoom (e.g. Pentax 55-300).
As with many primes on APS-C, vignetting is essentially a non-issue in both.
The Chinon shows more fringing wide open (and the Tokina wasn't exactly a champ here), in return it has somewhat less of this oldschool greenish tint and gives a bit better contrast. (Its internal blackening appears to be worse than the Tokina's when looking in from the front, but from the back you can see that it actually does better when "torture testing" it with a flashlight from the front. Greenish cast actually is virtually a non-issue for both lenses when inspecting them visually, both are doing well in this test.)
Its image comes out a hint darker for the same settings, which we could chalk up to aperture calibration.
The usual non-tragic amount of CA is apparent.
The indoor flare test indicates considerably better suppression of veiling flare when compared to the Tokina.
Both of these lenses appear to employ a mix of multi- and single-coated elements (as it still was usual at the time – fancy coatings on large elements simply cost money), though the distribution is different. The Chinon may be more smartly designed here, since while the single-coated element with its yellow reflection is plainly visible, the last element is multicoated instead and should do a better job keeping sensor flare in check.

When compared to the Sigma 70-300 DG OS, the modern-day telezoom comes out ahead in terms of center sharpness and isn't worse in the corners, plus it doesn't have severe fringing either. However, the old prime is a good bit brighter for the same settings, and it does a much better job keeping blues intact. I guess even with improved coatings, all these surfaces in the modern lens do take their toll.

Overall, a decent performer if nothing particularly exciting. Still, it arguably is the best of my vintage 135s, and I'd probably have to resort to a less old (or at least more fancy) lens design for any significant improvement, like the Pentax F or at least A series 135. Anyway, at least it's not as big and cumbersome as the Sigma 70-300, and should thus prove handy when some tele action is needed.

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Summing up: Old MF lenses

I have been collecting inexpensive manual focus lenses for a while now, so let me sum up a few general impressions.

Old MF lenses generally get you good mechanical build for the price.

In general you're best off with primes, but zooms with moderate zoom ratios can be rather decent. The definition of "moderate" would depend on how old the lens is. In the 1970s, few lenses with zoom ratios of more than 2 were good (though exceptions did exist), whereas nowadays a ratio of 3 isn't a problem and 4 to 5 may still be rather good. Zooms usually have a lot of lenses and as such benefit from modern coatings. When an old zoom is good, it tends to be heavy. (This is true for zooms in general.)

Even primes are not necessarily up to the standards of modern high-resolution DSLRs (>6MP on crop). Those in the once-common 50-55mm range usually are, assuming coatings are half-decent. However, don't be surprised if ones towards the wider end are equalled or outpaced by a lowly modern-day kit lens (at least when lens correction comes into play), at least those that you can pick up inexpensively. Don't even bother with anything wider than 24mm. Towards the tele end, things are similar. Your average run of the mill 135mm will be fine for 6MP but show its limits at higher resolution. Again, a modern-day telezoom may well be at least equally good while providing comfort features like image stabilization and autofocus.

Wading through old house-brand lenses can be quite instructive, but is equally suited to make your head spin. Keeping track of all the variations made by various OEMs (in search of that diamond in the rough, of course ;)) is a real challenge.

I think the most bang for the buck is provided by a smart combination of old and modern-day lenses. In the Pentax world, it almost seems foolish not to have an old 50 or two, whereas at significantly different focal lengths, something a little more modern may be the better option.

BTW: Why doesn't anyone make decent, moderately-priced primes any more? They tend to be fast and correspondingly expensive, big and heavy. Sure, now there's the Pentax DA 50mm 1.8 (if you want a modern AF lens and one of the millions of old MF ones won't do), the nice and unsurprisingly well-selling DA 35mm 2.4, and you can get an overpriced 40mm pancake lens if you really want. There's been enormous progress in making zooms, which I guess are what sells in big volumes these days, but those tend to be rather big and heavy (or less heavy and flimsy). It's about time someone makes a kick-ass but affordable 28/2.8, 85/2-2.8, 100/2.8 or 135/2.8-3.5 again. A decent 16-18/2.8-3.5 (crop only) wouldn't hurt either, as it's useful for walking around in cities or indoors. (Sure you can buy a 21/3.2 Limited or a 15/4 Limited, but like any Limited, these are low-volume items with impeccable build and carry the kind of price tag that goes with these factors.)

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SMC Pentax-M 50mm 1:1.7

After having tried so many third-party 50mm primes, I felt it was time to try a Pentax one. So I snatched one up inexpensively that turned out to be in decent shape (a dust speck on one of the inner elements excepted; apparently this one was opened at some point, as some haze on one of the inner elements has also been cleaned off somewhat incompletely). It isn't reputed to be the greatest 50 ever, but should definitely be decent. It employs 6 elements in 5 groups, fairly typical for lenses like this. 49mm filter thread. S/N 45xxxxx. (It is not clear whether all S/N ranges do in fact perform identically. These lenses were available for quite a while and, being common kit lenses, sold in significant numbers.)

This is a fairly compact lens, a little shorter than the M 28/3.5 even. It's about as big (or rather compact) as the optically similar Rikenon P 50/1.7, but using a lot more metal, it's heavier at 185 grams. Focus distance indications are seen in a cutout, as on other Pentax lenses, and 0.45m to infinity is covered in a turn of about 210° with the expected level of smoothness. The aperture can be set from f/1.7 to f/22 with clicks not only at full stops but also in between – f/1.7, *, f/2.8, *, f/4, …, f/16, f/22. The 6 aperture blades are slightly curved, but this results in a rather kinky "circular saw" type shape at the first intermediate step and at f/2.8, the worst such case I've seen so far. (The Auto Revuenon / Chinon 50/1.4 is much better behaved in this regard. Its lens barrel is marginally bigger, too, but can this account for the difference?) It looks completely normal by f/4.

Optically you almost cannot go wrong with a decent 50mm lens, and this one is no exception. I was obviously eager to compare it to my trusty Rikenon P, but the weather wasn't, so I had to resort to indoor tests at first.

The "point it at a bright light source" test showed roughly comparable performance wide open, with a good bit of blue fringing that quickly diminishes as you stop down. However, the Ricoh lens showed a small greenish flare, while I couldn't find any on the images of the Pentax lens. A testament to the superiority of SMC coatings at the time, no doubt. (The Auto Revuenon / Chinon 50/1.4 showed a barely visible purple flare, and that's a 7-element/6-group job, so not too bad at all. Then again, the XR Rikenon equivalent showed none at all. It also seems to resist veiling flare very well, actually best among all my 50s. I can generate heavy veiling flare on both 1.7s if I want to, even the Auto Revuenon 50/1.4 seems at least as good. This was quite surprising, as I would have expected lenses with more surfaces and a bigger front lens to be more susceptible to flare. Looks like the optical formula plays a big role in flare sensitivity, possibly even more so than the actual coatings. Judging by susceptibility to veiling flare, it seems that SMC coating is not superior to conventional MC at high incident angles, or at least wasn't back then.)

Sharpness wise, the M 50/1.7 is just fine. Compared to the Rikenon P counterpart using the same optical formula, there's not much in it in terms of center sharpness wide open, though spherical aberration fringes seem somewhat better controlled and the image turns out punchier. (I'd say spherical aberration haze is just about gone by f/2.3 or whatever that first intermediate step is.) However, the Pentax lens fares distinctly worse in terms of sharpness in the outer regions. By f/2.8, those have caught up but still are a bit less sharp compared to the Ricoh lens. By f/5.6, there really is very little in it. I do not see the kind of big differences observed in this test in the macro range involving the Rikenon P 50/2, a lens very similar to its 50/1.7 cousin (unlike the Pentax-M 50/2, which is a 5/5 setup). Then again, I haven't thoroughly evaluated performance at very close distances yet, though at about 0.9m and f/2.8 the Pentax-M did in fact appear to be slightly less sharp than the Ricoh lens.

Testing for greenish cast by looking at a white wall through the lens surprisingly indicated somewhat less good light transmission than in the nearly-transparent Rikenon P counterpart. It just about equalled the presumably single-coated Porst/Cosinon Auto 50/1.7 only (which uses a different optical formula with 6 elements in 4 groups). Mind you, this still is not bad performance at all, but makes me wonder what the cause could be, considering that coatings seem to perform well. It has to be the glass or cement or something. I am aware of the yellowing issues in old lenses using thoriated glass, but the M50/1.7 is too new for that.

Quite ironically, among all my lenses with a 49mm thread, the M 50/1.7 takes the most convincing to accept the JJC PH-SA49 replica lens hood; I already thought it wouldn't do so at all.

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Porst Color Reflex Auto 50mm 1:1.7 (M42)

Somewhat by accident I ended up with this M42 lens for very little money. At the very least I'd be able to use the 49mm screw-in rubber lens hood that was on it, I figured. This one apparently shipped with the Porst reflex C-TL and C-TL II middle-class SLRs (rebadged Cosina Hi-Lite HDL and 402), starting from about 1975. It thus can be assumed to be identical to the corresponding Cosinon Auto. The optical formula is given as 6 elements in 4 groups. These are single-coated with two different coatings that look amber and purple/magenta; multi-coating was already available on more upscale lenses at the time (like the 55/1.4, or Pentax' SMC Takumars of course, which appeared in 1971) and would eventually go mainstream just a few years later. The lens barrel is tapered so as to accept 49mm filters (and 51mm push-on lens hoods like the one it came with).

The design of this lens really screams 1973. (Its origins seem to be some time around 1972/73, still with slightly different knurling as found as a kit lens on the Cosina Hi-Lite EC.) Black with chrome was all the rage back then, and so it features no less than five (!) chrome rings in total. Not unusually for an older lens, it appears to be built like the proverbial tank – all metal, even the focus grip is. This reflects in a healthy weight of 214 grams.

Production appears to have lasted until the late 1970s, when single coating meant it was moving more and more down-market. By about 1978, this same lens with some external differences shipped with a camera bearing Porst's lesser Carena brand name, as a Super Carenar on (I think) the SRH1000/1001 models.

The focusing ring was rather tight when I got the lens (Cosina doesn't exactly enjoy a reputation for using the very best lubricants), but it loosened up nicely after a few turns. It moves rather lightly now, though it has a tendency to seize back up after a while. Typically for Cosina, it turns in the opposite direction when compared to Pentax, covering 0.5m to infinity in about 270°. The aperture is a rounded 6-blade affair much like on my Chinon and Tokina lenses, and its shape is well-behaved. Both automatic and manual aperture operation are supported. Settings unsurprisingly start at f/1.7, with clicks every half stop between f/2 and f/11, which then is followed directly by f/16 – no f/22 on this one, but two intermediate clicks between f/1.7 and f/2.8 in return.

As was the case with the Pentax-M equivalent, the JJC PH-SA49 replacement clip-on hood also is a very tight fit here.

Due to circumstances at the time, I did not yet have an M42 adapter. Picking one turned out to be somewhat non-trivial, with loss of infinity focus, tricky removal, upside-down lenses and burrs in the M42 thread not being uncommon with inexpensive ones. You can obviously hold the lens in front of the camera, but that isn't an awful lot of fun. (I eventually got one with only minor burrs in the thread and 10° or less of offset that I robbed of its locking mechanism as I found removal to be too fiddly and unpredictable. Nowadays you can thankfully get the better-finished Pentax original for less than what I paid back then, the locking mechanism will come off in the same manner if need be.)

When compared to my newer 50/1.7 lenses using 6 elements in 5 groups (rather than 6 in 4), the actual length between front lens and last element is a fair bit smaller, and the last element protrudes further into the camera. In combination with a longer lens barrel this means that the first element is fairly deeply recessed, providing a good level of inherent flare reduction. The "point it at a bright light source" test indicated why: A combination of a yellow and purple flare was seen here. Not too distracting, but not exactly flawless performance either, and ranking behind my other 50s save for its 6/5 PK mount successor. Perhaps even more importantly, sensitivity to veiling flare is higher than in any 6/5, in both this and the MC version.

Wide open, this lens exhibits quite a bit of spherical aberration haze, especially towards the edges, so its images are not as punchy at this point as, say, the Pentax-M 50/1.7's. This haze reminded me of the Porst 28/2.8 auto F in quality, also being more or less neutral in color but spread out further than on newer constructions that tend to exhibit purple seams. It still is quite pronounced by f/2 and only really clears up by f/2.8. Detail retrieval wide open already strikes me as very good, on par with or possibly even better than the Rikenon P, even towards the sides. However, at smaller apertures it is quickly overtaken by its newer cousins, having a bit of a hard time shaking off its significant astigmatism. I'd look at a shot and say "hey, that's good", only to switch over to the Rikenon P's and find that one to be even better. (To be fair, that Ricoh lens truly is an excellent performer at larger apertures. The difference to, say, a Pentax-M or -A 50/1.7 at f/2.8 is much smaller.)

Just like on my other 50/1.7s, lateral CA is pretty much a non-issue in practice. Still, it is among the strongest in the group.

Contrast actually is not generally inferior to its newer multicoated cousins, so they've certainly made the most of the coatings. (It will appear that coatings for the 4 groups are amber – magenta – amber – magenta, i.e. directly opposing glass surfaces have a complementary spectral response to further deter light from bouncing around between them, which can be a real problem if they are almost parallel and close or concave and facing each other.) Once I was comparing apples to apples, it did no worse on my indoor test target than the Rikenon P! Looking in from behind, internal blackening strikes me as good, which certainly plays a role here. However, single-coating does have its limits, as indicated by the flare test, and veiling flare may well compromise contrast under adverse lighting conditions. So do give it a nice hood.

Bokeh is on the nervous side, especially in the front. This lens exhibits oldschool circular "swirl" bokeh (highlight discs get elliptical when moving away from the center, not to mention their reasonably pronounced outer rim). This sometimes can be used to good effect, but most of the time it's only distracting. Thankfully things normalize by about f/2.8.
"Swirly" bokeh is a pretty sure sign of a lens design predating the use of computers. (It can be quite extreme in pre-war lenses.) Probably some sort of Biotar-alike in this case, which is actually known for generating bokeh like that and also features 6 elements in 4 groups. Designs like this appear to have been reasonably common for 50mm f/1.7 to f/2 lenses in the '60s and '70s (e.g. Nikkor-H Auto 50mm f/2 up to AI Nikkor 50mm f/2, Auto Rikenon 50mm f/1.7, Yashinon-DX 50mm f/1.7 and who knows how many else), though the first ones like the aforementioned Zeiss Biotar date back to the 1920s/1930s already.

Checking for a greenish / yellow cast by looking at a white wall through the lens, I found transmission about on par with the Pentax-M counterpart (or my best 28s), though it's not quite as clear as the Rikenon P or my 135s (these three are my best lenses in this regard). A good result, particularly when considering the older coatings. Actually a cross-check with the later MC version indicated virtually identical transmission, which thus appears to be glass limited.

Overall, I rather like the Porst (Cosinon) Auto 50/1.7. It's a joy to handle with its all-metal build, does a good job on sharpness when stopped down like 50s usually do, has "swirly" bokeh at large apertures if you like that, and it's quite common and cheap around here. It's not a match for any of my newer 50s with 6 elements in 5 groups when it comes to performance wide open (manufacturers with more conservative ratings sold lenses like this as f/2), and will also require some more attention to veiling flare than more modern designs with better inherent flare resistance and better coatings.
A newer multicoated version does exist, also in M42 mount, though it's a little less common and build is slightly more basic; I found it to be much less of an improvement in practice than I had anticipated. Most of the K-mount versions that you'll be seeing use a different optical design, they are (competent but overall unexciting) 6/5s.

Actually I did eventually find the multicoated version of this exact lens after all, as the kit lens on a more upmarket Porst C-TL super from about the same vintage (1975-ish), a black version of Cosina's Hi-Lite 405 I think – a chunky, heavy, solid beast that fully matches its kit lens. Nowadays the MC is in the bag more often than not. That should tell you a thing or two! (That said, I have been hard-pressed to find major performance differences to the single-coated version, even though reflections do differ. I think the first element has reddish multicoating on the outside and bluish on the inside, the second group features amber single coating, and all the rear elements are multicoated in greenish turquoise.)

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Revuenon MC Macro 70-210mm 1:2.8-4

This is a one-touch telezoom from the mid-'90s, or so I infer from a 94xxxxxx serial number and a PK-A/R mount. Its automatic aperture is thus usable on both Pentax and Ricoh SLRs (and Pentax DSLRs), but focusing is fully manual. MF lenses already were on their way out at the time. It says JAPAN on the barrel, which I assume means it was made by Cosina – at least it was them who made a Vivitar lens with identical specs and features, including the 1:2.5 macro mode, and later they also offered an AF version with the same 1.1m minimum focusing distance and 62mm filter thread. Remaining stock of this one was sold new in the 100..150€ range in the mid-2000s and considered good value at the time. Both the older Vivitars and newer AF Cosinas are stated to use 14 elements in 11 groups, so we can assume this one also does. Compared to the Sigma 70-300 DG OS, this lens is somewhat longer at 70mm and somewhat shorter at 210 (135mm / 162mm), and it's slimmer in diameter (lens barrel 68mm, grip 74mm). Even without a lens hood, however, it is somewhat heavier at 737 grams.

Build is reasonably reassuring, actually being mostly metal with a rubber grip. The metal is coated with something to give it a matte surface. The aperture ring is plastic, however, and while the aperture values are molded in, the others appear to be just silkscreened on and potentially subject to wear. Speaking of apertures, all the values from f/2.8 to f/22 are offered with full-stop clicks, no surprises there. The aperture itself consists of 9 blades, with a resulting shape that's only approximately round, being somewhat potato-shaped. That doesn't exactly instill too much confidence in the construction of the aperture mechanism, even if I've seen similar in Porst 135s also presumed to be built by Cosina. Focusing operates smoothly. There is a bit of zoom creep, but it really is very slow and by no means as bad as on my Pentax-M 80-200/4.5.

Optically this lens strikes me as decidedly average in sharpness. It's not totally unusable but soft wide open, and you're best advised to stop down a stop. The corners further improve thereafter, but remain somewhat softer than the rest. Actually 210mm turned out to be somewhat more convincing than 70, in return I still some blue fringes at f/5.6. Resolution is barely adequate for film, I'd say. At least lateral CA seems to be fairly well-controlled and is virtually unnoticeable.
Bokeh seems typical for a zoom like this, neither bad nor great.

In terms of brownish/greenish tint, this lens had some more than the more modern Sigma 70-300 DG OS, but less than the old RMC Tokina 75-150, so I guess it slots in where it should in terms of complexity and age.

Well, I guess this lens showed some promise, but a hidden gem it probably is not. Where 10 or 15 years earlier Quelle's photographic house brand Revue had graced fairly competent products (and in fact, other technical products also did well), it had moved down-market in the time that followed. Besides, zooms and AF had taken over by the early 1990s, and things were shifting rapidly in the SLR market. Chinon, previously being one of the primary suppliers of their better gear, were unsuccessful in establishing an AF system of their own, and eventually stopped making SLRs altogether. (They did produce some pretty cool-looking bridge cameras until about 1993 or so, when they got a deal for OEMing cameras for Kodak, who later ended up taking them over.) Apparently Cosina also quit making them some time in the 1980s, concentrating on their core business of lenses instead (they're OEMing for Zeiss these days). Ricoh never made the jump to AF and dragged on until the late 1990s, eventually establishing a niche in the digital compact camera market (they ended up taking over Pentax recently). A Chinese Seagull (a Minolta clone) enjoyed some popularity in the early 1990s under various brands, but the days of the generic SLR were definitely over. Even established brands like Pentax found themselves struggling and forced to compete on price in the mid-'90s, which didn't exactly do lens quality any good – several models from that time enjoy the reputation of being flimsy and not particularly durable.

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Light transmission ranking of my lenses

Many lenses have a bit of a color cast to them, imposed by imperfect spectral transmission of antireflective coatings or the glass (or optical cement) itself. It usually is brownish / greenish with some variation to one direction or the other. It generally is the worse the more glass-air surfaces a lens has (hence usually worse for zooms when compared to primes), but the better the more modern the coatings are, though I have found significant variation apparently caused by glass alone. As quite rightfully pointed out in this article on the "real" speed of fast lenses, advancements in optical glass have not exactly been unimportant (remember that a lot of work went into making glass for fiber optical connections more transparent, or else they wouldn't have been feasible the way we know them today).

A number of old high-performance lenses using elements containing radioactive substances are also known to be affected by browning (actually it's the cement they use, thankfully restored to normal by generous exposure to UV light), but I have none of these.

I have assessed transmission of my lenses by eye, looking through any two of them at a uniformly illuminated (6500K fluorescent) white wall while compensating with aperture settings as needed. This is a somewhat tedious process as differences can be extremely small, and I have come up with a slightly different ranking for some lenses on retesting more than once, with no small number of them being essentially tied, plus how are you supposed to be ranking a difference in tint? Anyway, here they are from best to worst:

Rank	Lens (#Elements/#Groups)	Notes
1	Rikenon P 50mm 1:1.7 (6/5) DA 35mm 1:2.4 (6/5) AGFA (Chinon) MC 135mm 1:2.8 (4/4?) Pentax-A 50mm 1:1.7 (6/5) Pentax (K) 135mm 1:3.5 (4/4) RMC Tokina 135mm 1:2.8 (5/4?)	Just about perfectly clear; est. ~0.1 stops
2	Porst (Sun?) MC auto D 135mm 1:2.8 (4/4?) Porst Super-WW-AS MC G 28mm 1:2.8 (7/7?) Auto Revuenon (Cimko?) multi coated 35mm 1:2.8 (6/5?) Porst (Sun) MC auto F 28mm 1:2.8 (6/6?)	Slight cast only; est. ~0.2 stops
3a	Pentax-M 50mm 1:1.7 (6/5) Pentax-M 28mm 1:3.5 (6/6) Auto Revuenon (Chinon) MC 35mm 1:2.8 (5/5) (Dad's) DA 55-300 1:4-5.8 (12/8) Pentax-M 35mm 1:2.8 (6/6) DA L 18-55mm 1:3.5-5.6 (11/8) = DA 18-55mm 1:3.5-5.6 AL WR (11/8) DA 16-45mm 1:4 ED AL (13/10) Sigma 55-200mm 1:4-5.6 DC (12/9)	Still pretty good, most of these are basically tied
3b	Sigma 70-300mm 1:4-5.6 DG OS (16/11) XR Rikenon 50mm 1:1.4 (7/6) Porst (Cosinon) MC Auto 50mm 1:1.7 M42 old (6/4) Porst (Cosinon) Auto 50mm 1:1.7 (6/4, single-coated) Porst (Cosinon) MC Auto 50mm 1:1.7 M42 newer (6/4) Sigma 17-50mm 1:2.8 EX DC HSM (17/13) CZJ Tessar 2.8/50 S/N 47xxxxx (4/3)	Still pretty good, most of these are basically tied; the complex Sigma 17-50 slotting in here shows how far technology has come; DxOMark: Tloss for Sigma 70-300 ≈0.3 stops *)
4	Pentax-M 80-200mm 1:4.5 (15/12) Pentacon 3.5/30 (5/5) AGFA (Chinon) MC 28mm 1:2.8 (?7/7?) Vivitar (Komine) MC 28mm 1:2.8 (#K03) (?7/7?) Sigma UC Zoom 70-210mm 1:4-5.6 AF (?13/9?)	Rather decent, esp. for zooms, and downright spectacular for the old and complex M 80-200
5	Revuenon MC Macro 70-210mm 1:2.8-4 (14/11?) **)	OK, reflecting complexity and age of this mid-'90s telezoom
6	Porst (Cosinon) MC Auto 55mm 1:1.4 M42 (7/5) Porst (Cosinon) MC Auto 50mm 1:1.7 PK (6/5) Auto Chinon MC 50mm 1:1.7 (?6/5?) Auto Revuenon (Chinon) MC 50mm 1:1.4 (7/6) RMC Tokina 75-150mm 1:3.8 (12/9) Zeiss (Jena) "Zebra" Sonnar 135mm 1:3.5 (4/3, single-coated) Alfo Supercolor MC 28mm 1:2.8 (?6/6?)	Only average; expected for an old zoom and not unusual in early-'70s and older primes but subpar for a prime from around 1980 and newer (like the Porst and Chinon 50/1.7 jobs); est. ~0.4 stops for the first few to ~0.5 stops for the last three
7	Tokina AT-X 28-85mm 1:3.5-4.5 (S/N 83xxxx) (?14/9?)	Significant brownish/green cast and light loss, reflecting complexity and age of this zoom; Tloss must be >=0.6 stops

Please note: Depending on the specific spectral absorption function, these results may not accurately reflect the color accuracy seen when used with a camera employing automatic white balance and should only be taken as a rough guide. Comparative eyeballing does not exactly count as precision measurement either.

Putting things into perspective:
Loss in both single- and partially multicoated 6/4 M42 Porst 50/1.7s (group 3b) is virtually identical, i.e. either glass/cement limited or about 4 surfaces of different coatings don't make a major difference. Two of them put in series have as much light loss as the newer PK mount, 6/5 model (group 6). And one of them in series with the newer model loses about as much light as the Tokina AT-X 28-85 (group 7), i.e. that one has about three times as much transmission loss as one of the 6/4 M42 Porst 50/1.7s (and since I now have three variants of them, I was able to compare all 3 in series to the AT-X zoom, and it's a very close call). These must be at about 0.2 stops then. My clearer lenses must be at 0.1-ish stops, in line with what good modern 50s tend to achieve. In fact, stacking Rikenon P 50/1.7 + DA35/2.4 gets me to about M28/3.5 level, slightly above the 6/4 Porst 50/1.7s.

*) You have to be careful when using DxOMark's transmission rating to calculate transmission loss. They can only tell what the lens lets through at open aperture, which is a result of both actual geometric aperture and transmission loss, so the difference to the manufacturer's official rating does not reflect transmission loss alone. If it were, some zooms would have transmission gain for some focal lengths (see e.g. DA 18-55 II).

**) Lens subsequently sold and no longer available for testing.

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SMC Pentax-A 50mm 1:1.7

This is the successor to the corresponding M type with an automatic aperture (so you can use it in program mode), introduced in 1984. S/N 15xxxxx.

Size wise, this lens is just as compact as its predecessor, but build is more on the level of the Rikenon P counterpart now – plastic with a metal mount, though it does retain a rubber focus grip, and the actual lens barrel seems to be metal, too. The weight accordingly drops from 185 to 164 grams. Focusing is slightly rough in places on my sample, and the aperture ring requires a good bit of force.

While the optical formula remains 6 elements in 5 groups, it seems ever so slightly different from both the M type and the Rikenon P counterpart. Lens coatings have also changed, the bluish reflection from (I think) the second element is gone. Finally, aperture shape is significantly better-behaved, being almost back to normal at f/2.8 and only somewhat odd-looking at f/2.4 (the M type was quite bad in this respect). It does close a little unevenly on my sample, not looking too great at f/22 and f/16. Apparently the lens designers knew, as intermediate (half-stop) clicks are only available down to f/11.

Light transmission used to be a little worse than expected on the older M type. That has been corrected in the A type, which finds itself among my clearest lenses. Sharpness looks to be about comparable to the predecessor so far, my sample doesn't seem to focus quite all the way out to infinity though (maybe a few dozen meters max, which doesn't quite cut it by modern-day pixel peeping standards). Looks like I'll have to fix that.

I do like the original Pentax lens caps that came on both this and its M series counterpart.

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Porst Tele MC 135mm 1:2.8 auto D (ø55) / 135mm shootout

I've got a thing for these store brand lenses, eh? After having obtained two rather similar 135s, I figured I'd try out one that's a bit different, and suffice to say I was not disappointed in that regard. I think that this K-mount lens was made by Sun Optical. It's got a rattly aperture mechanism like my Porst 28/2.8 auto F has, which I presumed to be Sun-made. It also shares the same bayonet cap and push-on lens cap (60mm OD), though the integrated hood means the actual filter thread diameter is slightly smaller at 55mm. Serial number 819xxx, with no space between "No." and the first digit, just like it was on the 28/2.8. The "auto D" designator would indicate a 4-element affair, presumably in 4 groups. Total length from the mount is about 83.5 mm at infinity, lens barrel diameter is 58 mm, outer grip diameter is 63 mm. I've also seen this one sold as an Avanar. It appears that there are two subtly different versions – mine is the one whose hood does not slide in under the focus grip and which also has a narrower DOF scale ring (presumably it's newer, as samples of the other one sported 812xxx and 796xxx serial numbers).

Compared to the Tokina and AGFA/Chinon counterparts, there are two properties of this lens that stand out: It is a fair bit lighter at 364 grams, and it is longer, a good 5 mm more from the mount, which optically becomes more like an 8 mm difference. At the same time, the last element is not as deeply recessed into the lens, so the optical formula appears to be substantially different. The aperture ring moves lightly and smoothly, with half-stop clicks available between f/4 and f/16. Aperture shape is slightly rounded down to about f/4. Focusing is damped much more heavily, which exposes some play in the mechanism (the Tokina counterpart is similar in required force but shows no play). Effective lens hood extension (from front lens) is about the same as for the Chinon.

Initial tests were limited due to the weather at this time of year. I did find the usual generous amounts of fringing wide open, but central sharpness appeared promising even in overcast conditions, though it seems you'll have to stop down quite a bit for it to extend into the corners (bottom right is particularly problematic and quite blurry at f/4). I also noticed a fair bit of lateral CA. Focusing duly extended to infinity or a bit beyond; mimimum focus distance is the classic run-of-the-mill 1.5m. Looking through the lens, I found the ring-shaped flare at the outer edge of the front element absent that I'd seen in my other 135s. (Possibly their first three elements are similar to the Pentax-M 135/3.5's, while in this one they look more like in the K 135/3.5 or A 135/2.8.) As the lens also appears to be multicoated throughout, there's hope for good contrast. Light transmission is slightly lower than for my other 135s but still good absolutely speaking – about comparable to the Porst 28/2.8 (again) or slightly ahead of the Pentax-M 50mm 1.7.

Interestingly enough, the indoor flare test involving my flashlight provoked the worst veiling flare among all my 135s when the light source was just outside the field of view. The RMC Tokina proved better but still not great, and the AGFA/Chinon fared best by far. Now when looking in from behind, a rather shiny metal ring is seen among or right behind the front elements of the Porst, which may explain why it struggled in this discipline.

For fun, I did some test chart shooting with all my 135s, using a tripod and live view focusing, at a distance of about 2.6m. The results proved quite interesting. The Porst auto D turned in the highest amount of CA (while the other two were just about tied), but it wasn't that simple when resolution was concerned. Here's the resulting JPEG (*** quality) file sizes in MiB for all aperture settings, as an indicator of captured detail:

Lens → Aperture ↓	Chinon MC	Porst auto D MC	RMC Tokina
f/2.8 1/30 s	3.74	3.82	3.95
f/4 1/15 s	4.09	4.07	4.13
f/5.6 1/8 s	4.21	4.18	4.12
f/8 1/4 s	4.19	4.15	4.12 *
f/11 1/2 s	4.16	4.17	4.19 *
f/16 1 s	4.03	4.02	4.09 *
f/22 2 s	3.83	3.80	3.92 *

*) Note that from f/8 onwards, this lens consistently is about 1/3 stop brighter than the other two, i.e. real aperture is larger than indicated. Accordingly, dispersion limiting is expected to be less bad.

Wide open, the Chinon shows the highest amount of blue fringing and the Tokina the least, which duly reflects in file sizes. (And I used to think the Tokina was bad for longi CA…) The Tokina still gives the most competent impression at f/4, if by a narrowing margin. However, it fails to gain any more resolution up to f/8 and only peaks at a nominal f/11, which is in line with my impressions of it taking very long to sharpen up. By f/5.6, the other two leap to the front, with the Chinon actually delivering its best resolution. Its left-hand side is somewhat weak at this point though, and the other two look better there. (Note that I could not reproduce a particularly weak LHS in part 2, which was set up more carefully.) It's also got some odd CA near the center which is virtually gone again by f/8. Most consistent across the field: Tokina.

For CA correction in the Porst when using Pentax Utility 4, try values like -12 for red and -7 for blue.

In part 2 of this shootout, I dragged the trusty Tokina 75-150 zoom onto the battlefield, carefully adjusted to match the Chinon in focal length. In comparison to the rather predictable primes, this one had some oddities to offer. CA most definitely varies when stopping down, which I think partly explains why JPEG images at f/8 commonly came out smaller than at f/5.6 (CA seems to increase file size). I also noticed that some moiré disappeared by f/8, but overall the image looks much nicer as the lens shakes a significant degree of astigmatism in the outer regions.

By f/11, the 75-150 eventually catches up to the Tokina and Chinon 135 primes at f/8 (minus a bit more lateral CA). Kind of makes sense given it's a stop slower to begin with. Wide open, it exhibits some vignetting, and resolution is only average (some wacky field curvature at work there, it seems), but spherical aberration is well-controlled even at this point, and large-scale image contrast is in no way inferior to the Chinon prime. Sensitivity to veiling flare is average and might be about on par with its Tokina prime colleague – plus there is no integrated hood. Bokeh in the front looks just like the Chinon's. Lateral CA is somewhat worse.

I also compared the Chinon and Tokina primes again. At f/8, they are more alike than different. CA looks somewhat different but is at a comparable level overall. The Chinon seems a smidgen ahead in sharpness, in the outer regions in particular. Go to f/5.6, and the Tokina's CAs become more disturbing. Ironically, it also is a bit softer on the left this time. In return, the Chinon shows first traces of its blue fringing tendencies. The fringes grow at f/4, in return the Tokina becomes softer. Wide open, the Tokina shows a mix of spherical aberration and purple fringing, while for the Chinon it's blue fringing of about equal magnitude. The blue fringing may be a bit more annoying, but in return the Chinon exhibits less vignetting, and overall it's hard to tell a winner. Same goes for sharpness, which seems more affected by minor differences in focusing.

The Porst also does fairly well at f/8, with sharpness being somewhere in between the Tokina and Chinon 135s. It hasn't lost its higher CA levels though, which are a little worse than in the 75-150 still.

Finally I brought in the Sigma 70-300 DG OS. Compared to any of the others, it is undoubtably huge. But what about image quality? I set the focal length a little short of 135 mm (which turned out to match the other lenses best; the lens called it 123 mm), disabled OIS and started out at f/4.5. That wasn't too convincing yet, a little soft with some spherical aberration haze. f/5.6 proved a little better but still not exciting (aperture wide open seems to be a little short of its stated f/4.5 to begin with, so the difference to f/5.6 is quite small). By f/8, however, the lens left all the old primes in the dust, with better sharpness and much better-controlled aberrations. Plus, having OIS increases the odds of actually being able to stop down that far (at least on my K-x with its rather limited sensor shake reduction effectiveness). Granted, it appears to be more sensitive to blurring from mirror slap than some of the others, but then again this is not a "tripod lens" and asking to be used handheld with OIS on instead.

I am under the impression that by the time my 135s were made, the golden era of the 135 was already over. They say that there is no such thing as a bad 135 (even though some dogs do seem to exist), but there must be an awful lot of average ones and very few great ones. The push to f/2.8 and falling prices in the 1970s must have accelerated this even further. I don't think there is any "generic" 135 from around 1980 that deserves to be called excellent.

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28mm indoor shootout

Photography can be quite uneventful in wintertime. It's commonly cold and dark outside, which isn't too inviting. So, what's a bored hobby photographer to do? Well, I grabbed Dad's solid video tripod of yesteryear and had some fun shooting test targets. The outcome of tests in semi-controlled conditions can be quite interesting.

After I had already taken a look at my 135s, I thought why not look at 28s next?

The candidates

I have quite a few lenses that qualify:

AGFA / Chinon MC 28mm 1:2.8
Pentax DA L 18-55mm, f/4.0 @ 28mm
Porst 28mm 1:2.8 auto F
Pentax-M 28mm 1:3.5
Vivitar 28mm 1:2.8 (K03)
Tokina AT-X 28-85mm, f/3.5 @ 28mm

That's a total of 4 primes and 2 zooms.

So I proceeded to set up the tripod, got about as close as 0.9m (at least that's what the distance scales indicated on average) and took some shots. As usual, RAW with development in Pentax Utility 4, lens correction off.

Wide open: f/2.8

A comparison of the results delivered by the three f/2.8 lenses more or less repeated previous findings. The Porst auto F is only usable as a "soft focus" lens wide open, lots of spherical aberration haze means a distinctly fuzzy picture even when viewed at small scale. It also shows considerable vignetting. Not to mention that its CA is already plainly obvious at this point.

The two remaining contenders (Chinon and Vivitar) rank much more closely. Their results both look acceptable when viewed fullscreen. There is a comparable degree of vignetting (noticeable but not dramatic). Zooming in reveals considerable blue fringing (longitudinal CA) on the Vivitar. Basic sharpness already is decent though. The Chinon shows very little haze and no blue fringes, but this sample gets distinctly fuzzy towards the left (which improves on stopping down but never quite disappears). Too bad.

Wide open: f/3.5 – f/4.0

All of the three less fast candidates yield decent results wide open. The Pentax-M prime shows noticeable vignetting, while the kit zoom is a bit better behaved, and the Tokina AT-X takes the lead in this discipline, with hardly any vignetting at all. The Tokina zoom brings up the rear in terms of contrast though, owing to its complexity and age. It also shows a latent degree of fuzziness (indicating some spherical aberration remaining), but at least sharpness remains quite even across the field. The Pentax kit zoom, almost up to the victorious Pentax-M prime near center, is affected by astigmatism in the corners and yields the worst result of all three there.

Interestingly, at the same claimed f/3.5, the Tokina zoom is about 0.2 stops brighter than the Pentax-M prime, which in turn is about as bright as the kit zoom claiming f/4. Metering with the Pentax-M also gave the same exposure time as for other lenses at f/4, leading me to believe that its f/3.5 specification is rather on the optimistic side of things. Maybe someone thought an f/4 lens wouldn't sell, or didn't want to admit that the lens had actually become less fast when compared to its much bulkier K series predecessor. Make no mistakes, it's still a fine little lens.

General observations

Among all 6 lenses, CA arguably is lowest in the Pentax-M. The Vivitar is a little worse but still rather decent. The kit zoom is best described as middle of the road, same goes for the Chinon. CA levels are fairly high in the Tokina zoom (as I noted when reviewing it) and highest by far in the Porst prime.

The Tokina zoom is long enough to yield a noticeably different perspective.

I am guessing that nobody will be surprised by the least complex lens (Porst auto F) taking longest to sharpen up, while the most complex one (Tokina AT-X) comes close to optimum sharpness little more than 1 stop from maximum aperture.

- work in progress -

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Sigma UC Zoom 70-210mm 1:4-5.6 AF

A very small amount of money brought me this estimated early-'90s autofocus telezoom with push-pull type zooming. It is quite a bit more compact than the 70-300 DG OS, which while a nice lens, strikes me as a tad too big and cumbersome. When retracted at 70mm, it's only about as big as the Tokina AT-X 28-85, and weighs in at 422g (bare) or 457g with lens hood. It takes the common 52mm filters, and in fact I received a fancy multicoated UV filter with the lens (not like I ever use one, besides this one has a fair bit of transmission loss). Note that the front element rotates when focusing. Lens configuration appears to be 13 elements in 9 groups, without any fashionable aspherical or ED elements in sight. (Interestingly, a less common UC APO version also seems to exist.) The supplied round lens hood attaches via a bayonet mount (and can be put on upside down for storage), although it only seems to twist on until it's tight without explicitly locking.

Mechanically it is a part metal, part plastic affair with rubber grips, famously employing tape underneath to hold some things in place (the front group and an internal cover, to be precise). You get a nice clicky aperture ring with half-stop steps throughout. The aperture itself is a 6-blade affair that is visibly rounded down to about f/5.6. Focus distance indications are seen underneath an acrylic window, similar to Pentax lenses of the time. Almost the entire surface has a rubbery feel to it, even the metal parts (lens barrel, aperture ring) appear to have been coated with some sort of rubbery material. Zoom creep is reasonably well-controlled, certainly no comparison to my M 80-200 4.5 that'll move when you look at it the wrong way.

Inside, I can spot a number of multicoated surfaces, and surprisingly, at least two uncoated ones (not an unusual cost-cutting measure in zooms at the time, apparently). In terms of optical performance, this lens seems to be about what you expect, nothing special but decent, your typical "nice weather lens". At 135 mm, it still is a bit soft and fringy wide open (which it says is f/4.5), but quickly improves when stopping down. By f/6.7 it becomes usable if still a little weak in the corners, and ultimately reaches Porst 135mm f/2.8 auto D level at about f/11. CA levels are rather similar then, too. Contrast doesn't strike me as any worse either, and transmission still ends up in the "decent" camp. Aperture calibration is good when using the aperture ring, not so much when using auto mode and setting things on the camera.

My sample apparently has some issues, mostly mechanical in nature. First of all, it's got severe backfocus when using the AF (what should be about 2.6m becomes more like 3.2m at 135), which seems to be almost gone at the long end and worst at the short end. I have my doubts about infinity focus calibration, too, which seems to be just a little short of what it should be, especially at the more critical long end. There also is quite a bit of slack somewhere in AF transmission (I can easily go back and forth between about 4m and 4.8m with AF on, and no, this lens has no quick-shift). I don't think the gritty noises heard in some focus areas are entirely normal either. (The lens hood shows some signs of having banged against a white wall or something, and the hood attaches to the focus ring, so I consider it quite possible that a drop could damage something in the focusing mechanism. I did check the tape under the focus grip that holds the front group on, it seemed to be in fine shape.) The previous owner must also have been a heavy smoker, even the inside of the lens appears to be smelly (ugh). No, I don't think they took good care of their equipment. Mind you, I still easily got my money's worth out of it.

Assuming my sample worked correctly, I'd easily prefer it to the big clunky Revuenon 70-210 2.8-4. Unlike that one, it's heard of the term sharpness at least. Think kit lens level or so. Plus it's nice and compact. I don't think it's quite as good optically as my old Pentax-M 80-200 4.5, but obviously that one is longer, heavier and totally annoying to use because of major zoom creep in my sample.

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Alfo Supercolor mc Auto 28mm 1:2.8

This PK mount 28 appears to be pretty common here in Germany. Again, it's one of those store brand lenses (ALFO belonging to the local Ringfoto chain in this case). It's an intermediate length, somewhere between my Vivitar and AGFA/Chinon 28s. Uses a 52mm filter thread. Fat chrome trim on the front of the focus grip. Front lens diameter has got to be the smallest of all my 28s, about 28mm only. Weighs 216 grams. Going by reflections, it appears to be a 6-element job (presumably in 6 groups). The serial number on mine is 90xxxx, but I don't think this means it was made in 1990 – 1979 is far more likely. It might not have anything to do with the year at all.

I'm not sure who made these; the otherwise common "LENS MADE IN JAPAN" inscription is conspicuously absent, so it may be a Korean-made piece. Overall, build reminds me of the Ricoh(/Sears) 135mm 2.8 the most. I've also sighted a single-coated Auto Revuenon version (in both M42 and PK mount, marked "PU" and "PK" on the aperture scale, respectively) – look for a relatively small lens with two tiny holes in the aperture ring (left of the scale). A multicoated Hanimex version in PK mount also exists, marked "SP-MC AUTOMATIC". Serial numbers seem to be in the 90xxxx range for these as well. Finally, I also spotted a "Super Albinar MC" version (in PK). As you can see, we're talking the crème de la crème of lens makers. ;)

Build quality feels plenty decent on this one, as you may already have suspected from its weight (it's actually my second heaviest 28/2.8). It's all metal with a rubber grip, and all the scales are engraved. The aperture ring moves lightly and precisely, providing half-stop clicks from f/2.8 down to f/16 (then the next step is f/22). Aperture shape gets jagged at f/3.3, which reduces at f/4 and leaves a rounded aperture down to about f/5.6. Focusing smoothness isn't groundbreaking but OK (possibly some dried-out lubricant). Minimum focus distance is a rather average 0.36m, but the focus ring turns a whopping 270° – the same stats as on the Porst auto F, with which it also shares a seemingly identical mount and similar aperture mechanism. Possibly parts were sourced in Japan but assembly was in Korea, and/or the lens design was licensed or somesuch? I've sighted similar Japan-made lenses, too.

A look through the lens reveals transmission that's not an awful lot better than for my Chinon 50s, i.e. rather average and behind any of my other 28s. The same also goes for resolution wide open, there really isn't much, and you also get a fair bit of spherical aberration haze and, of course, visible vignetting. f/4 is kinda usable. In order to be able to speak of any kind of sharpness, you should stop down to at least f/5.6. At f/8 it reaches optimum center sharpness and gets pretty good across the entire frame, although getting the last bit of astigmatism out of the corners requires f/11. In the f/8-f/11 region, sharpness actually does not need to hide from the Pentax-M 28 3.5.

There's a bit of lateral CA, but it really isn't too bad at all – a little behind the Vivitar K03 maybe. I think that applies to the entire performance of this lens. Wide open it may even be a smidge worse than the chunky Porst auto F (another 6-element job), but when stopping down it overtakes that one by about f/4 and eventually leaves it far behind, with better sharpness across the field and far less lateral CA. Contrast and colors seem fine, though no doubt the latter were helped by AWB action. You do get a slight color cast under some conditions, but contrast actually is in the same league as the Pentax-M 28 3.5.

Flare sensitivity seems about average. Shooting into a bright light source reveals fairly obvious bluish ghosting, possibly sensor flare. (Maybe coatings aren't that great? The Auto Revuenon/Chinon MC 35/2.8 shows this to a much less disturbing degree, and I could not find any on the AGFA/Chinon 28/2.8 and the AGFA/Chinon and Tokina 135/2.8s, let alone the DA L 18-55. It could be that the sensor sees some of the mount's shiny chromed surface surrounding the innards at the back, as those have a smaller diameter than on most of my other lenses and so the remaining ring around them is relatively wide. Actually this lens is holding the record in that regard here, followed by the Porst auto F. And what do you know, that's how they rank blue flare wise. Interestingly the 35 would not flare at all this time.)

A review of the Auto Revuenon counterpart (which was found to be similarly meh) mentioned barrel distortion. Yes, this lens does exhibit some, though I specifically had to look for it, indicating that the amount should be totally noncritical in general shooting. (On a 1.5X crop sensor, that is. The guy with the Auto Revuenon used a full-frame camera, where it would be expected to be more pronounced.)

I'm guessing that this one was a cheapie back in the day, and it sure performs like it. Realistically this would have made a decent f/4 or so (unsurprisingly so with its 6 elements, where all my better 28s have 7). Still, it should be plenty useful as a "nice weather" lens in good light, when you can stop down to f/8-f/11 and obtain perfectly fine pictures (f/5.6 should do for smaller-sized prints). Granted, you might just as well use the "lowly" 18-55 kit lens then (which may not be as sharp in the center but does better in the corners)… Do not buy one of these as your first prime expecting awesome performance, it would be a major disappointment. If all you want is a (very) cheap and usable lens to get a feel for the build and operation of these old manual primes, why not.

On "overspec'd" lenses

One of the typical differences between a big-name lens and a lesser (3rd-party) one is usability near maximum aperture. Now granted, the big players have a reputation to lose and the lesser ones will happily offer the same aperture at a lower price even if optical performance isn't up to it. But is it really that simple?

Well, I don't think it is. There is one other factor at least: Viewfinder brightness. Say you have a lens configuration that would make a decent f/4 at best. It will be a fair bit darker than an f/2.8. So there is an incentive to make a lens whose performance wide open is OK for a viewfinder but needs to be stopped down for decent photographic performance.

There seems to be a tradeoff associated with this, however. Look at the Vivitar K03 28mm f/2.8 and compare it to the Pentax-M 28mm f/3.5 which is much the same size. It needs 7 elements to achieve roughly comparable performance to the slower 6-element Pentax lens of similar vintage.

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Auto Revuenon (Chinon) MC 35mm 1:2.8

This is the last lens I got in last year's (2012) buying spree. Alas, this was near the end of the photography season (around Christmas), and so it got neglected for a while. But rejoice, it will now receive some attention.

35mm was a rather common focal length back in the day, and as such it should be no surprise that there are a number of Revuenon branded 35/2.8s. Mine is a Chinon twin externally (like the 50/1.4), but I've also sighted Cosina and Cimko (!) versions. And that's just PK mount, in M42 they also had Sun-built ones and Korean pieces (Samyangs). What a mess. My lens features a 49mm filter thread and came in both PK and M42 mounts. It has its serial number at the side of the barrel like my other (presumed early/mid-'80s) Chinon lenses, whereas older samples (with a 52mm filter thread and "multi coated" spelled out) typically have theirs on the front ring.

This lens is about as long as your average 50/1.7 and a bit slimmer. It employs all metal build with a rubber focus grip, as usual for primes at the time, and weighs in at a moderate 180 grams. Just like on my 50/1.4 (and a number of Pentax lenses), a 49mm filter thread is provided. Close focus starts at a rather good 0.3m, with infinity reached after a turn of about 210°. Aperture settings of f/2.8 to f/22 are available, with full-stop clicks. The hexagonal aperture is slightly rounded down to about f/5.6 and does not get terribly irregular even at f/22. The aperture ring is a bit on the stiff side.

My sample appears to have had a fair bit of use. It is the first of my primes to exhibit noticeable play in the barrel, the paint on the aperture ring is visibly worn, and the focus rubber grip has lengthened somewhat and is slightly loose (though it still provides good traction). (In the meantime I've swapped rubber grips with a "parts" Chinon 50/1.7 whose aperture is an oily mess. Funnily enough, both lenses seem to be happy now.) The push-on front cap (seemingly non-original) has also seen better days. Usually wear on a 30+ year old lens is a good sign – it can't have been that bad if it was used this much.

Optically, we seem to be looking at 5 elements in 5 groups, with 2 elements in front of the aperture and 3 behind. (Name-brand 35/2.8s of the time tend to be using 6 elements in 5 or 6 groups, so this one is not quite as fancy.) The color of reflections (brownish, magenta, yellow, blue and green) seems to suggest a mix of multi- and single-coating. The outside of the front lens gives a lightly bluish reflection, not sure how effective that would be (anyway, this is the least critical surface, assuming you do not decide to use an uncoated filter). The people designing these Chinon lenses appear to have put a fair bit of thought into optimized but cost-effective coating solutions.

So, how does the lens perform? Wide open, we're seeing a decent level of sharpness, with some of the expected blue fringing, some astigmatism in the corners and a moderate amount of vignetting – not exciting but usable. Things much improve when stopping down, with no more vignetting and good center sharpness at f/4, though you'll want to give the corners f/5.6 or f/8. Center sharpness is excellent by f/5.6, where actually most of the frame does well. Corners are visibly soft at large apertures even at reduced size (indicating an MTF graph that starts dropping quite early there), and some astigmatism does remain visible in the extreme corners even at f/8 when viewed at 100%, so f/11 may be needed if you're picky about that. Lateral CA is low to very low (a second sample proved even better). Contrast appears to be fine – not like you'd be expecting any major problems or anything, with only 5 elements and multicoating. Transmission is just fine, too, being better than for its (AGFA) 28/2.8 cousin as well as the Vivitar and Alfo 28/2.8s, about on par with the Porst 50/1.7 M42 and Pentax-M 28/3.5, and a smidgen behind the big Porst auto F 28/2.8.

Shooting into a bright light source reveals little in terms of ghosting, only a slight blue ghost that appears when stopping down, from about f/5.6 on (or maybe that's the ominous sensor flare?). Otherwise you have to have a strong light source near the center of the frame to produce flare, and how often does that happen? Using an uncoated filter produces a pronounced bluish-turquoise ghost at all apertures, as one might expect. This test also shows how blue fringing, still quite pronounced wide open, is much reduced one step down and a non-issue by f/5.6, where only a hair of reddish CA seems to be apparent. Sensitivity to veiling flare seemed about average.

It looks like aperture calibration on this lens is noticeably off, losing diameter when stopping down. Its f/16 looks more like f/22 on the Pentax-M counterpart (so I would assume that it's half a stop down in the middle position, making f/6.7 more like a real f/8) - though interestingly enough, images seem fine in actual use. The second sample I obtained (in better cosmetic shape) is even worse, catching up to f/16 somewhere in between a nominal f/8 and f/9.5 and actually producing noticeably darker images at the same settings. So be very careful when conducting comparisons. Those are the little pitfalls of mass-market consumer-grade lenses, I guess…

I've had a bit of trouble focusing both samples out to infinity at times. #2 seems to be stopping at about 10 m right now, #1 is a bit better. I am guessing that infinity calibration is pretty tight to begin with (going hyperfocal instead may have been considered more user-friendly in the film era), and a slightly longer-than-specified register in the camera and thermal expansion are conspiring.

Overall, this is a good "second-tier" lens. While probably not a match for a big-name counterpart, especially wide open, it quickly gives good results when stopping down. It's usable wide open if need be (unlike that Alfo 28/2.8, which still is somewhat worse at f/4) and leaves fairly little to be desired by f/5.6 to f/8. As typical for an old prime, the corners aren't that hot, but if it's any consolation, the K series Pentax 35/3.5 suffers from much the same. Judging by how beat-up my sample is, the previous owner knew that they had a good performer on their hands. Shame about the aperture cheating / inconsistency though. Now the kit lens isn't exactly a slouch at 35mm either, so I guess I'll have to conduct a little shootout there.

It is quite apparent that making a decent 35mm lens is a fair bit less hard than the same exercise for a 28.

Fun fact: When I got the Pentax-M counterpart, I found it to be a respectable performer – however, a little comparison yielded no clear winner, neither wide open nor stopped down. If anything, the Chinon lens was the sharper one at f/4. Even bokeh wide open is quite similar, with maybe a slight advantage for the Pentax lens. In return, results in macro on a 20mm extender were reversed, as were CA levels. Whoever designed this little Chinon lens must have been a pretty smart cookie. Getting equal performance out of 5 elements rather than 6 is no mean feat. Of course SMC coating being what it is, I'd expect better flare resistance in the Pentax.

For the promised shootout, I dragged out the chunky Tokina AT-X 28-85 and the trusty DA L 18-55 kit. Both of them seemed to agree that the 35 actually is a hair longer than specified (or, being IF lenses, their effective focal length drops at close distances, where I compared FOV; the Pentax-M 35/2.8 seemed to share that opinion though). The outcome was quite predictable actually – the kit lens presents itself as the allrounder that does not obtain highest center sharpness (which does not improve from where it is wide open @f/4.5) but gives solid results across the frame, the Tokina obtains very good center sharpness when stopped down but struggles with sharpness and CA in the corners, and the Revuenon gets sharp in the center quickly while the corners need a fair bit of stopping down to catch up, making it to kit lens level eventually.

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Porst Color Reflex MC Auto 50mm 1:1.7 (PK)

No, I didn't need another 50. Yes, I bought this one anyway. (It wasn't that expensive, which helped.) I believe it's a rebranded MC Cosinon-S 50mm 1:1.7, the orange bump gives it away. (One without the bump would be the older and pretty rare version that's optically identical to the screw-mount MC Auto.) The focus grip pattern would seem to date this one to '78/'79-ish, and it was apparently sold as a kit lens with the Porst compact reflex OV (rebadged Cosina CS-2), available from 1978 on. 49mm filter thread, fairly lightweight at 171 grams.

This PK mount lens measures 2 or 3 mm longer than the venerable Pentax-M counterpart, but the front element actually is more recessed (though not as much as on the older single-coated M42 Porst) and somewhat smaller. I wouldn't be surprised if this were actually identical to the far more common 1:1.8 Cosinon-S. That one is supposed to have 6 elements in 5 groups, and a look inside my lens appears to confirm this – the first three elements give six reflections in total.

The lens is built from mostly metal with some plastic and a rubber focus grip (which slips on my sample, as apparently it's only held in place by tension and the surface underneath is smooth). Scales are engraved. The construction strikes me as more dust-prone than some, especially at close focus. Aperture settings are basic, full-stop clicks between f/2.8 and f/16 and none between f/2.8 and f/1.7. The aperture itself is a reasonably well-behaved but not particularly rounded 6-blade affair. Focusing runs between 0.5m and infinity in a 180° turn. (Only the Rikenon P counterpart has even less focus throw, but it has a larger MFD as well.)

The bayonet is anodised black, so some sanding action opposite the mount contacts will be necessary for correct metering.

Transmission is only average for this one, much like in corresponding Chinon lenses. In fact, it barely edges out the Chinon 50 1.7, if that. (Unfortunately I cannot review the latter as its aperture is an oily mess.) AWB usually takes care of the greenish/yellow cast though.

Sharpness wise, this lens struck me as an average performer in its class. Much like my other 6/5s, It's usable wide open, certainly more so than the older M42 counterpart. The outer regions are still soft at f/2.8, but by f/5.6 it's nice and sharp almost everywhere, though I must say that when stopped down, the older lens left a slightly better impression still. Lateral CA proved to be very well-corrected though, the Rikenon-P is quite a bit worse (as is the predecessor). There is the usual dose of longitudinal CA at large apertures though. Vignetting is very similar to the Pentax-M counterpart in both shape (sort of a brighter central patch) and extent. It is inconspicuous even wide open (I had to take white wall test shots to find it) and gone by f/2.8.

Bokeh appears to be decent, certainly better than in the older M42 lens. Bokeh circles have a slightly brighter border, but it's not too bad at all. Wide open they seem to expose some lens separation going on at the edges in my sample.

Flare immunity is rather lousy and about on par with the old single-coated M42 lens only (well, it does produce discrete flares that are about equally strong or even stronger, though susceptibility to veiling flare is reduced). It's easily the worst among all of my 6-elements-in-5-groups 50s, with bright, cyan-colored flare. Looking at the lens, it shows much stronger reflections for the rear elements when compared to its 6/4, M42 mount MC predecessor (actually it's even outdone by the old single-coated lens), including – who would have guessed – a nice and bright cyan one. Among its 6/5 kin, it still takes last place. The Chinon counterpart is somewhat better, the Rikenon P better still, and nobody will be surprised to be seeing the SMC Pentax lenses doing best.

The coatings found on this one remind me of some of my RMC Tokina and Chinon lenses from about the same time, colorful but not all that great.

In sum, a decent 50 that was built to a price (hey, it was a kit lens for an ordinary mass-market SLR after all). It generally is a competent performer, with excellent lateral CA levels on the positive side and lousy flare sensitivity on the negative one.

After leaving this one on the shelf for a while, it seems that lubrication has just about entirely dried up, and focusing now is pretty rough. Ugh. Cosina and their lubricants…

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Porst Super-WW-AS MC G 28mm 1:2.8

Oh no, yet another Porst-branded MF lens. This one's a Japan-made cutie, barely measuring 63mm in diameter and 34mm in length at infinity (which is 3mm shorter than the Pentax-M 28 3.5). The respectable weight of 216 grams betrays the 7-element lens though (in 7 groups, apparently). PK mount (but also available in M42 – apparently "AS" stands for "Adapter-System", so mounts are changeable à la Tamron). 49mm filter thread. S/N 17xxx.

Except for the rubber focus ring, the lens is all glass and metal. Focusing operates smoothly, covering 0.25m to infinity in a 180° turn. The aperture is a 5-blade affair as seen in Pentax 28s, with half-stop steps provided down to f/16, which is directly followed by f/22. Aperture operation is light, smooth and precise. Scales are engraved. In short, nice build.

I did find out that these lenses were first introduced in 1980, and with the switch to Fujica SLRs in 1981/82 they can't have lasted that long. Who made it is rather nebulous though, as e.g. Tamron 28s are totally different. It does bear some resemblance to the Komine-made "Close Focus" Vivitars but there are some distinct differences. For one thing, this one has a rather bulbous front lens, and then there is not a single screw to be seen on its mount (something not even the M42 Porst 50 1.7 can claim, where 3 tiny screws are on the outer perimeter). Makes sense if the mount is supposed to be swappable though. There is a flange at the rear element but offset about 90° from the aperture lever. Interestingly, the aperture is not fully opened at f/2.8, which together with a comparatively large rear element suggests that this one may originally have been an f/2.5 design. (Turns out the clicks are offset a bit.)

My best guess right now would be that Porst had these lenses custom-made, possibly by Kiron if the light blue "AS" is any indication (could also be Tokina or Sun though). Meanwhile, I've spotted a Hanimex-branded clone (one of almost a dozen 28/2.8s that they sold), presumably with a fixed mount – the one discussed here. Not sure what to make of this.

A look through the lens reveals that transmission is excellent. In fact, I'd say it handily beats the Pentax-M 28mm 3.5 here, which is no slouch to begin with, and even edges out the chunky Porst auto F. Not bad at all for a 7-element / 7-group lens with seemingly run-of-the-mill ca. 1980 multicoating. Heck, at least two of the rear elements (possibly all three) and two front elements only look single-coated to me.

On camera, this lens delivers perfectly usable images at f/2.8 already. There is some fringing and some halos, of course, but the extent is rather well-controlled. Vignetting is virtually inexistent at this point on APS-C – I can hardly spot it even on test shots. Things do eventually get blurry and astigmatic when approaching the corners, but that was to be expected. By f/3.3, most of the spherical aberration haze is gone, and this setting should be quite usable all-round already. Now unfortunately while the lens does improve when stopping down further, it never really gets pin sharp (i.e. beyond kit lens level) or totally even across the field. This sample also shows some decentering, performing worse on the right – not terribad like my AGFA/Chinon sample, mind you, but the amount of CA over there does get rather noticeable. CA is odd in that it is maximum not at the corners but rather partway out.

Bokeh doesn't seem to be particularly smooth, with slightly brightened borders on bokeh circles indicating overcorrection of spherical aberration (not unexpected in an older design tweaked for best wide-open performance, besides so-so bokeh isn't unusual in older 28s in general). Aperture shape also is slightly irregular at f/3.3 before transitioning into a well-behaved rounded shape from about f/4 on (visibly rounded down to f/6.7 or so).

Results on the test bench were somewhat sobering. Mind you, the lens did do well, but at the same aperture the Pentax-M 28 3.5 was sharper in the outer regions (even wide open) and showed better contrast, not to mention less CA, with only some vignetting wide open holding it back. Even the lowly Alfo Korea special had perfectly fine contrast and proved by no means inferior to the big guns at f/8, save for some CA in the outer regions (but again, it's not like the Porst didn't have any) and a slight color cast. The two other lenses also agreed about the Porst's actual focal length being a bit longer than specified.

I guess the lower contrast is why I thought the Porst lacked that "bite" in terms of sharpness when stopped down, since its resolution is about in line with the others. It seems 7 elements in 7 groups and sucky coatings don't mix. Also note that the last element in particular only has amber single-coating, which typically doesn't work out too well on DSLRs – and in fact, on my indoor test subject nominally dark grey shadows would attain a brownish cast while color rendering was very close to the reference otherwise. An amber back element is very typical for lower-end Tokina lenses from that time, so maybe they OEM'd this one.

The verdict: The Porst Super-WW-AS MC G 28mm 1:2.8 is a good performer when you actually need f/2.8 (I am most convinced by the f/2.8 to f/4 range), but nothing too special by f/8, with contrast being a little short of what it could be on a DSLR (some correction in post may be advisable). A decidedly "film era" lens. Transmission is excellent though, as is build quality.

How to remove the "AS" mount adapter

Turn focus to minimum focus distance.
Set aperture to f/22.
Grab lens so that one hand holds the aperture ring and the other holds the focus ring.
While depressing the locking pin in the DOF scale ring, turn bayonet (including aperture ring) clockwise.

Getting things back together is a bit fiddly.

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Lens Coatings: The Fine Print

Having handled a number of lenses now, I must say that antireflective lens coatings are a nontrivial subject.

For one thing, coatings are not all created equal. Multilayer coatings do vary in performance a fair bit, for example, even if they usually outclass their single-layer predecessors. Single-layer coatings may still vary in material (usually MgF₂ but occasionally fancier / more expensive ones) and thickness (to optimize for different wavelength ranges).

In addition, "multicoated" / "MC" does not generally equal a fully multicoated lens! You should not be surprised to find surfaces giving the characteristic reflection colors of single-coatings in 1970s/1980s lenses, or a few entirely uncoated surfaces in 1990s/2000s ones (as single-layer coatings had been discontinued by then).

For eventual lens performance, it is important how different coatings are combined. In addition, don't discount the influence of general lens construction. Lacklustre internal blackening may well degrade contrast of a lens with multicoated elements severely (to be observed in some Russian lenses), while a well-thought-out design with a smart combination of different kinds of single-coating may give perfectly fine contrast. (The combination of different coatings is also used to optimize transmission across the visible spectrum.) Single uncoated elements are not necessarily tragic either, assuming they are faced by multicoated ones and curvature of their surfaces is different enough to dissuade light from bouncing back and forth between them.

As an aside, the rear surface coating of the very last element has been found to be critical on DSLRs, as their sensors are more reflective than film. The common amber single-coating in particular seems to result in sensor flare or reduced contrast easily, depending on how the last element is shaped. Unfortunately, this is precisely the setup found on otherwise competent RMC Tokina series lenses around 1980 (apparently most of them including my 75-150 3.8 and 135 2.8, plus 28 2.8, 35-70 3.5, 50-200 3.5-4.5 and others, with the notable exception of the 17 3.5), as well as the Porst Super-WW-AS 28mm 2.8 and the older single-coated versions of the fabled Tomioka 55s, plus whatever else of old lenses with all amber single-coating there is still around. By contrast (pun not intended), all of my nominally multicoated lenses from Chinon, Cosina, Sun and Vivitar (Komine), the Ricohs plus the single-coated Porst (Cosina) 50/1.7 either have magenta or blue single-coating or some sort of multicoating on the last element.
Note that I have also found sensor flare to be caused by reflective lens parts seen by the sensor – again, general lens construction at work.

The maximum number of acceptable groups of elements while maintaining good contrast seems to be about 3-4 with single coating (somewhat more when multiple kinds can be combined, maybe 4-5), 6-7 with average multicoating or a mix and 10+ with first-rate multicoating.

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Porst Color Reflex MC Auto 50mm 1:1.7 (M42)

Yet another variation on the Porst 50mm 1.7 game: A multicoated one in M42, kit lens for the Porst compact-reflex S and SP models (Cosina CSR) in 1977. (A PK mount version must also have existed, sold with the short-lived OS model at the time, but I've never seen that one.) This one is sort of a hybrid between the two others – at 185 grams, it is already built more lightly than its single-coated (or less common multicoated) predecessor and features the somewhat reduced focus throw of its PK mount successor, with a shorter lens barrel and thus less deeply recessed front lens, while retaining the 6-elements-in-4-groups optics (now largely multicoated) and nice rounded 6-blade aperture with half-stop steps. 74xxxx serial number.

In general, the lens performs much like its older single-coated counterpart. That includes circular bokeh with pronounced rings around bokeh circles, and a fair bit of spherical aberration haze wide open. It should not come as a surprise, however, that the comet-like flare when shooting into a bright light source is a fair bit weaker. Otherwise, contrast seems much the same and, if anything, more influenced by the presence of a hood. Transmission is virtually identical between the two, giving only a slight yellowish cast – it thus appears to be dominated by glass and optical cement.

Fun fact: If I put both of these lenses (this one and its single-coated predecessor) in series, their transmission is pretty much the same as that of the newer PK mount, 6/5 model. And one of them in series with the newer model loses about as much light as the Tokina AT-X 28-85, i.e. that one has about three times as much transmission loss as either of my Porst/Cosina M42 50/1.7s. These must be at about 0.2 Tstops then.

Compared to its predecessor, there are some subtle but interesting differences. I was a little disappointed to find corner performance to be rather somewhat worse than in the older lens. That made some sense, however, once I found that actual focal length in this MC lens agrees closely with the Rikenon P, whereas the older single-coated version agrees with the Pentax-M counterpart instead, which is a bit longer (about 0.4mm or so). Now for a given effort, results tend to be best at 58mm, and the further you're away the worse performance will be. This is why 55s used to be popular SLR lenses, and why an f/1.2 Noct-Nikkor is a 58mm job and nothing else. 50mm was a popular focal length on rangefinder cameras, but the larger required backfocus distance on SLRs (you've got to fit that mirror somewhere, see registration distance) meant that initially the existing high-performance designs had to be scaled to 58mm. (See Zeiss Biotar 58mm f/2, a 1936 SLR design.) Eventually we did get true 50s, but everything else being equal, they'd still do a little less well and require more stopping down than their slightly longer colleagues. Now I don't think a 0.4mm difference should be that noticeable, but if the design actually isn't 100% identical, all bets are off. Plus, there's always that pesky sample variation.

Compared to the successor with a different optical configuration (6 elements in 5 groups), this lens surprisingly produces much weaker discrete flares. Looking at both of them, the newer lens shows much stronger reflections for the rear elements (arguably even stronger than on the old single-coated lens), so I'm guessing this is the reason. The old 6/4 scheme appears to be decidedly more susceptible to veiling flare though, so instead of discrete flare you are more likely to lose contrast under adverse lighting. (It's not something that you'd see in a good modern design, but this one basically dates from the 1920s!)

I would say that the second lens group in this lens is actually employing amber single coating, though the first element is multicoated (reddish front, bluish back). (This is the same as in the older MC version.) Well-working turquoise / greenish multicoating is found on all the rear elements.

As its successor, my sample of this lens also suffers from a slipping focus grip. There appears to be slight haze on the first rear element, too, it looks like this may have been cleaned non-ideally once (possibly this lens had an oily stuck aperture once and some oil had gotten onto this element as well).

To sum it up, it's a decent 50. Probably not a patch on other 6-in-4s like a Zeiss Planar 50mm f/2 rangefinder lens (which benefits from shorter registration distance / backfocus to begin with) or the Nikkor-HC 50mm f/2 SLR lens, but certainly acceptable. Compared to its successor, it's less good wide open, but thanks to multicoating, having bright light sources in the frame produces noticeably less obnoxious flare (not quite as little as a Pentax M or A counterpart, but certainly competent, though a stronger tendency to veiling flare does remain). It'll be my "circular bokeh for cheap" lens.

PS: Or at least it was, until I managed to obtain the less common MC version of the older full-metal lens.

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Sigma 55-200 1:4-5.6 DC

While I had a well-performing telezoom in the Sigma 70-300 DG OS, this one is quite large and cumbersome. While the old Sigma 70-210 UC Zoom had come close to my ideas in terms of dimensions, it was defective. I found that the current Sigma 50-200 DC OS HSM was being closed out cheaply, but sharpness towards the long end was reported to be modest. So when a used sample of the older unstabilized 55-200 DC came up on the 'bay, I decided to take a chance and gave it a shot.

This is a rather 2-ring compact telezoom. It's not an awful lot bigger than one of my 135/2.8s. The UC Zoom actually is shorter, but stouter and much heavier. The 55-200 is pleasantly light at 338 grams. There's not much in terms of frills save for the now-standard electronic innards that report the current focal length and set the aperture, and AF screwdrive. It comes with a round lens hood that twists on and can be stored in reverse, much like on the old UC Zoom. It uses a 55mm dia. filter thread, which seems a little excessive given that the front lens is actually smaller than in the ancestor with 52mm. Unlike in many other cheapie zooms, the aperture is an 8-blade affair, though not particularly rounded.

Zooming and focusing operate just fine, though for manual focusing you'll need to engage that on the camera. Minimum focus distance is 1.1 m, which is quite good at the long end and not exciting at the short end; there is no dedicated macro mode. Thanks to the light weight, zoom creep is kept to a minimum. These lenses enjoy a reputation of being a first-rate air pump, and there certainly is some truth to that. Not the right one to use in a damp environment for sure.

Optically, zooms like these rarely are wonder lenses, and this one is no exception. You should stop down to f/8 and preferably f/11 on the long end for decent sharpness. Performance is about in line with the old UC Zoom there. On the short end, f/9.5 still is a good idea. CA seems to be well-corrected, however, and contrast strikes me as good (even with what seems to be two uncoated and at least one single-coated surfaces lurking in there). Transmission also is quite good, being more or less in line with the DA L 18-55 kit.

At 135mm, there is a fair bit of spherical aberration and blur wide open, but even one stop down at f/5.6 things turn out a lot better, though sharpness steadily improves to at least f/8, and the corners get better at f/11. The lens eventually ranks behind the AGFA (Chinon) MC 135/2.8, which in turn is surpassed by the big Sigma 70-300 DG OS.

This lens enjoys a reputation for good bokeh, and it's doing quite well in this department for a cheapie zoom. Bokeh discs do have slightly brighter fringes towards the long end, and things definitely get colored there, but towards the middle and stopped down a bit it's looking pretty good. Subjectively, background blur is just fine.

All in all, this lens is just fine for what it is, an inexpensive, compact and lightweight nice-weather telezoom. It will probably not take kindly to being exposed to the elements, and you should be stopping down to f/8 to f/11 throughout. Don't expect it to outrun the sensor resolution of any current DSLR body. I'm still not sure when a lens like this is worth taking along; maybe when weight is to be kept to a minimum. Otherwise I'd be very tempted to lug along the bigger but better 70-300 instead. It's about time we get some nice and affordable moderately-fast tele primes again.

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Pentax DA 55-300mm 1:4-5.8 ED

This review won't be as comprehensive since technically it's Dad's lens. He insisted on getting a tele of his own and ended up with this popular Pentax offering. Compared to my Sigma 70-300 DG OS, it is quite barebones – while it does start at 55, it comes without a built-in stabilizer, uses bog standard screw-drive AF and is "just" f/5.8 rather than f/5.6 at the long end. They also managed to make do with a measly 12 elements in 8 groups, which 30 years ago would have made for a decent 80-200 at best – OK, there's some ED ones in there.

However, with the lack in features comes a surprisingly slim and lightweight lens. The Sigma is quite the beast in comparison. Now light weight isn't worth anything if results aren't up to par. Thankfully, they are. The long end already is usable wide open, with clearly less spherical aberration haze compared to the Sigma. Colors are beautiful, too, and in fact transmission turns out to be in good prime territory, excellent for a zoom lens.

It seems to run into its limits when used for macro at minimum focus distance at 300, where the outer regions of the image become decidedly blurry and bokeh turns slightly colorful as well. It does a pretty good job on people shots at shorter focal lengths though, even if bokeh seems somewhat more pleasing in the Sigma.

While the lens does deliver a good level of sharpness even wide open, it seems there are gains to be had by stopping down as far as f/11 on the long end – the moon seemed to benefit, at least. Normally f/8 should be fine there, but infinity seems to be a slightly different kettle of fish.

The lack of OS isn't as much of an issue on the K-5 it's normally used with, which unlike my K-x has rather effective in-body IS, though the less shaky viewfinder is somewhat missed. I did notice that AF with the K-5 + DA 55-300 combo would tend to hunt more often than with the K-x + Sigma 70-300 combo, presumably a result of the unstabilized lens. AF accuracy of this sample seems just fine throughout the entire zoom range.

In short, the DA 55-300 1:4-5.8 ED is a rather likeable modern telezoom. In classic Pentax lens fashion, it gives good quality images in a compact and lightweight package. It makes a good match for the modern Pentax bodies with their effective in-body stabilization.

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Pentax-M 35mm 1:2.8

Before splurging for a DA 35/2.4, I decided to give this old M series 35 a shot. It's a reasonably compact lens, being about the length of the M 28/3.5 and the diameter of the M 50/1.7. 49mm filter thread, 5-blade aperture with settings down to f/22, 175 grams. 6 elements in 6 groups.

The aperture ring offers settings of f/2.8, f/4, then half-stop steps down to f/16, finally f/22. More on that later. It looks and feels like a typical M series lens, no complaints there. Focusing extends from 0.3m to infinity in a 180° turn.

Unfortunately I found that my sample suffers from a seemingly common problem in these lenses, a slow aperture. This is rather unusual for Pentax.

As expected, I found it to be a competent lens – quite usable wide open and pretty sharp stopped down (not 50mm sharp but certainly better than my various 28s). Imagine my surprise, however, when I found that overall it did no better than the lowly Auto Revuenon / Chinon 5-element job (save for coatings, obviously). They were so close that I had to I had to conduct a controlled test shoot (on my trusty K-x, test target @ 1.3m) to find out how they differed:

Effective focal length of the M is slightly shorter, so maybe the Chinon is a little longer than specified after all.
They are about equal wide open, with some blue fringes in the Chinon vs. some spherical aberration in the M.
At f/4, the Chinon comes out first in sharpness (!), followed by the (not-so-)lowly DA L kit lens, and the M also has one rather weak corner.
I can't really decide who wins in central sharpness by f/8, it might be the M but its CA levels make this difficult to judge – let's say they're about equal. Both handily beat the kit lens that does not gain much by stopping down. (And let's not even get started about the 16-45 with barely kit-lens level center and fuzzy corners, which to be fair is weakest in the middle of its range while the 18-55 is just the opposite.) In the outer regions there's not much in it betweeen all three.
CA levels are about on kit lens level. The Chinon did noticeably better.

Bokeh wide open looks much the same between the two. Maybe a hair better in the M, but there's not much in it. In return, it only has a 5-blade aperture.
I tried both the Chinon and the M in macro mode with a 20mm extender wide open, the result with the Chinon seemed sharper (less blurry).
Transmission is very similar in both, this Chinon being maybe a hair ahead. Loss is about 0.2 stops or so.
There is some vignetting wide open in both on APS-C, though it's pretty much gone by f/4. It's arguably more disturbing in the M, where it's of the "central bright spot" type, compared to darker outer regions in the Chinon.

Possibly as a result of the slow aperture, I found that the lens slowly gets brighter when stopping down, gaining about an extra +1/4EV by minimum aperture. I am not a big fan of the somewhat irregular aperture shape reminiscent of a circular saw at about f/4-4.5.

This is a perfectly fine 35 with SMC coatings. It gets a fair bit sharper in the center when compared to the kit lens, but otherwise isn't truly a big upgrade (much the same CA levels etc. – granted, the 18-55 isn't exactly a slouch around 35). The lowly Chinon 35, presumably a somewhat newer design, pretty much matches its performance in spite of only using 5 elements, and cost me far less. Shame about the slow aperture, too. I guess the DA 35/2.4 is sorta inevitable.

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Auto Revuenon (Cimko) multi coated 35mm 1:2.8

Three years after the last entry here, LBA has struck again. This time I stocked up on 35s, both Revuenon branded actually – a less-worn Chinon variety as discussed earlier, and this one. PK mount, 52mm filter thread, all anodized black with engraved lettering (so green button metering will not stop down unless you are willing to sand down some of the anodizing where the contacts go), rubber focus grip with rhombic pattern, focusing turns the anti-Pentax way down to a measly 0.6 m, f/2.8 to f/16 with 6-blade aperture, "multi coated" spelled out on the front ring, green ft scale, 2xxxxx S/N. Going by the rhombic focus / aperture indicator and 4 irregularly spaced screws on the mount, I believe this to have been made by Cima Kogaku, probably related to the Cimko MT series. The aperture ring would appear to be metal though.

This is not the most compact 35/2.8 you will ever see. It is quite literally an entire centimeter longer than the Chinon variant (about 44.6 mm vs. 35.4 mm from mount at infinity), owing in part to a lengthy filter thread, and focus grip diameter is quite a bit bigger as well (about 60 mm vs. 56 mm). Quite unsurprisingly then, it doesn't feel too heavy for its size – at 192 grams, it does weigh a bit more than the Chinon version, but when picking both up you'd reckon it's the other way round. Aperture and focus rings feel solid but the helix could apparently do with some relubing, as focusing feels a bit rough (aside from being quite heavily damped in general). While minimum focus distance is rather pedestrian for a 35, a 150° turn means good resolution (the Chinon version will go down to 0.3 m rather than the 0.6 m offered here, but 0.6 m is reached after about 90° already). The 6-blade aperture (which is nice and springy) is noticeably rounded down to about f/5.6, and full-stop clicks are provided on the aperture ring.

Reflection counting gives 6 in the front and 5 in the back, pointing towards 6 elements in 5 groups. Coatings appear to be standard ca. 1980 Japanese partial multicoating, quite similar to the Chinon counterpart – nothing fancy, but gets the job done. The back element is the smallest in my 35/2.8s, with the Chinon Revuenon taking the lead and Pentax-M in between. Interestingly enough, the order reverses when stopping down.

First test shots in less than ideal weather indicate a good level of sharpness even wide open, with a bit of haze and less than ideal corners. I figured that transmission would be quite good from a tendency towards blue in outdoor shots (AWB in the K-x seems to be tweaked for somewhat warmer-rendering lenses), and in fact there only is a very slight brownish-green cast to be seen, putting it in the upper ranks of my lenses.

With better weather at hand, I was able to conduct some far-field test shots. You get a decent level of center sharpness and some spherical aberration haze wide open – not quite as good as the Chinon counterpart, but still usable. By f/4, sharpness is getting pretty good in the center and vignetting clears up entirely, while corners are still soft with some astigmatism. But then, when stopping down further, things actually start getting fuzzier in the center while sharpness further out keeps improving, like a ring of best sharpness that travels out. Kinky. That must be a donut-shaped MTF graph. As usual, there is little to be gained by stopping down beyond f/8 except in the extreme corners. There are hints of reddish CA in the outer regions of the frame but mostly it's a non-issue.

No complaints about general contrast. A bright light source in the frame will produce a fairly noticeable cyan-colored flare, so you may want to keep those out of the picture.

Overall, a decent if unspectacular lens. There probably isn't too much of a reason for getting this if you already own the 18-55 kit, which happens to be at its best around 35.

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Carl Zeiss Jena "Zebra" Sonnar 3,5/135

135 mm may not be my most-used focal length, but I wasn't overly enthused with any of my 135s, plus I was under the impression that this focal length had seen its best days well before 1980 and M42 may be the way to go rather than K-mount (though I guess I wouldn't mind a K series 135/3.5). So I ended up with this early-'70s East German Zeiss lens for a reasonable amount of money. Speaking of which, back in the day you would have had to fork over 229,- M (GDR Marks) according to the price tag on the box. The average worker back in the day may have made about, uh, like 600 a month or a bit less?, so in today's money this would translate to almost a thousand Euros. Suddely those Pentax Limiteds aren't looking so expensive any more…

This would seem to be the 4th version of the 135mm Sonnar, after an overhaul in 1967 that upped maximum aperture to f/3.5 but still without multicoating or an integrated lens hood. It's an M42 lens with push pin plus external stop-down lever, a 49mm filter thread, a minimum focus distance of a respectable 1 m and aperture autocorrection (as you focus closer and the lens moves out, effective aperture gets smaller, and the mechanism corrects for that, so it is recommended to go to MFD only at about f/4.5 and below). The aperture is a 6-blade rounded job (quite visibly so to about f/6.7), in old-fashioned bright bare metal rather than the usual black. Lettering is engraved.

Optical formula is an evolution of the classic pre-war Sonnar 135, using the same 4 elements in 3 groups, with classic all-bluish single coating as used by Zeiss since the 1940s. There's a fair bit of glass in there, which reflects in a measured 426 grams of weight, more than any other of my 135s (which are f/2.8 jobs to boot). Feels nice and chunky.

Handling is reasonably straightforward. Focusing runs in anti-Pentax direction and is reasonably heavily damped but not unpleasant (not unlike the Porst auto D 135). You should not forget to use the stop-down lever, as the lens does not offer a fully manual mode, but at least you'll always be able to get full viewfinder brightness. Some creativity may be needed for long-time exposure on a tripod, however.

While my other 135s are some of my clearest lenses, this one finds itself near the back of the pack, with a noticeable brownish cast. Then again, given the partly thick glass elements I'm not exactly surprised. AWB on the K-x tends towards the slightly warm side with this one.

Sharpness already is pretty decent wide open, with well-managed spherical aberration "glow" (it does become noticeable in night shots, turning bright white light sources blue). Around f/4, I'd place it slightly ahead of the RMC Tokina 135/2.8, which is similar in sharpness but has its share of CA near the corners; corners on the AGFA / Chinon 135/2.8 are just too soft at this point, even though it shows less CA. At f/5.6 and especially f/8, sharpness across the field beats even the Sigma 55-300. I still wouldn't say it's 50-level sharpness though. CA shows up in the form of some reddish fringes but generally is quite well-controlled.

Pointing the Sonnar 3,5/135 at a bright light source reveals rather noticeable flares where e.g. the AGFA Chinon remains entirely unimpressed – the old-fashioned single-color single coating would have to show up somewhere, right? You could probably do worse than giving it a nice lens hood outdoors. Shooting a plain white wall at f/22 also reveals a somewhat lighter bluish spot at image center (presumably back element and sensor interaction), though this probably is a total non-issue in practice. I only noticed because I was looking for dust on the sensor.

Bokeh is a bit oldschool, being somewhat busier than in more modern lenses. Still, I've taken some really nice macros at f/5.6 and minimum focus distance, which is shorter than for any of my other 135s even without extension rings.

This one's a keeper, I'd say. I still haven't found the 135 that would really blow my socks off though. I am guessing a Zeiss T* 2.8/135 would, but good luck adapting C/Y mount to PK. And you don't see F 135/2.8s around too often.

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HD Pentax DA 16-85mm 1:3.5-5.6 ED DC WR

Dad's birthday present for last year was a venerable Tessar 2.8/50 of about his age plus an M42 adapter, but that didn't go so well as the lens arrived misassembled and would need sorting out, besides he's more of a universal-lens AF type anyway. So as finances looked quite good this year, I decided to be mad enough to splurge on a Pentax 16-85 for him as he does take a lot of photos and the results from his 16-45 are not exactly blowing my socks off (outer areas at 16 in particular, maybe the well-documented wobble issue), plus focusing often kept hitting the stops at infinity on the wide end – the K-5 appears to be another of those cameras with a register that's rather a tad too large. I think they fixed that in newer models.

The 16-85 matches the K-5 well in size and weight (it's a fairly substantial lens at 488 grams), and the very quiet, quick autofocus matches the quietness of the camera as well (compared to the massive mirror slap on my K-x, the K-5 is downright stealthy). No complaints about general build quality.

When focused correctly, this lens will turn in some impressively sharp pictures indeed, with good rendering of details. The areas where it does ultimately lag behind a prime like the DA35/2.4 are CA levels towards the corners and maximum aperture. Still, consider me impressed. If what you need is an all-round lens, the 16-85 is a serious contender. It just seems that my K-x' autofocus system does not like it at all, as two different samples consistently presented significant backfocus on the wide end, while the second one proved close enough to LiveView on the K-5. I cleaned the bayonet contacts, no dice. Anyway, Dad's a happy camper now, which was the point of the whole exercise. Myself, I've been eyeing the Sigma 17-50 2.8 EX (non-OS) lately.

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Pentax DA 35mm 1:2.4 AL

Yes, there's that lens I'd been eyeing for quite a while. The "little plastic wonder" most presumably needs little introduction, being one of the go-to primes in the Pentax stable, but let it be said that it is a fairly compact (about as thick as a typical 50/1.7 but somewhat longer, 63mm dia. x 45mm long), very lightweight (125 grams) screw-drive autofocus prime. It's a fair bit bigger than my old Revuenon (Chinon) 35/2.8 but much lighter. Build reflects its low price point and is typical DA L level, read all plastic and no QuickShift or focus ring lettering (or WR) in sight, but still quite robust for what it is. While a DA series lens, it is actually full frame capable, apparently being based on the old FA 35mm f/2. No lens hood is supplied, you'll have to find one for a 49mm filter thread yourself – not too big a deal, on crop any typical "normal" lens hood should do just fine.

I scored a used sample in good condition, which shouldn't be that hard. These lenses are quite common and not overly expensive even when new. First impressions out of the box were very positive. This is a lens that you can actually use wide open or at f/2.8, assuming you don't look at the corners too hard. Good contrast even at this point, and you have to look really close to spot any fringing. Clearly longi CA is well-controlled – the Revuenon (Chinon) 35/2.8 (which is not a bad little vintage lens at all and about on par with Pentax' own M 35/2.8) still has a lot of blue fringes to contend with at this point especially if focus isn't bang-on, and resolution / astigmatism in the outer areas isn't anywhere close. (OK, we're comparing 1980-ish f/2.8 apples to at least 1990s f/2 oranges here.) Lateral CA is occasionally visible at high contrast edges in the form of slight red seams on high-contrast edges but generally is quite well-controlled, as you'd expect in an only moderately wide prime.

What jumped out at me almost immediately was how "pro" macro shots and the like looked, for lack of a better word. The things in focus really pop out very nicely, with smooth bokeh (though there's a region just in front of the subject that's prone to double contours). After all this quirky old glass, it's nice to have a thoroughly modern lens construction for a change. Speaking of in focus, this lens has a very plastic "3D" way of rendering detail, even though I haven't seen the kind of very fine detail retrieval of a good 50 yet. If I had to guess how the transfer function of the lens vs. resolution level looks like, I'd say it keeps things up well to a moderately high level, then maybe peaks, then tanks. Speaking of detail, I haven't been getting overly great results on landscape shots on my K-x, though the lens did fare about as well as the 16-85 on a K-5 with a roof ~10 m away.

Autofocus is noisy but generally very fast. Infinity focus proved tight on my K-x yet again, as if I needed any more confirmation that its register is rather longer than it should be. At least we can infer that infinity calibration on the lens appears to be quite accurate. (This is getting rather annoying, maybe I should finally send in the camera for service after all – focus accuracy for some kinds of targets indoors can be really bad, too, regardless of lens. Few things are more annoying than a fancy camera that fails to reliably focus on people's faces. The K-5 seems to share a lot of the same quirks when on center AF though.)

Light transmission on this lens is excellent and on par with the clearest lenses I have (like the Rikenon P 50/1.7).

You can provoke a spot of greenish flare by shooting into a bright light source, but on the whole I'd say flare resistance is very good, about on the level of my better 50/1.7s. It should generally be a non-issue in practice, certainly so when using a decent lens hood.

On the whole, this lens is a keeper. It should come in super handy for macro shots, low-light video, portraits and whatnot, size and weight should almost never be an excuse for not having it in the bag, and its retail price makes owning one pretty much a no-brainer once you are looking past the kit lens. I must say that on the K-5, the 16-85 zoom can very much turn in better results at times, though it better do for its substantially higher price tag, size and weight.

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Pentax DA 16-45mm 1:4 ED AL

Debuting way back in 2003, the venerable 16-45 was one of the very first DA series lenses, and being made until 2014, it had quite the run. In years gone by, it was one of the options you'd look at if you wanted to upgrade from the lowly kit lens (which may still have been the first DA 18-55 at the time, a somewhat worse performer than the 18-55 II, DA L 18-55 or 18-55 WR which feature a revised optical formula), especially if you could use something a bit wider or a brighter tele end.

I "inherited" this sample as it had been made redundant by a 16-85, which is in a different league altogether. At 388 grams (with hood) / 361 grams (no hood), it's a decent chunk of lens already. It's actually about the same length and a tad stouter than the old Tokina AT-X 28-85 zoom, but the barrel will extend quite a bit at the long end, and of course it uses a lot more plastic and is lighter. (Spoiler: This will be relevant later.) The lens came supplied with the usual bayonet-mounted tulip lens hood (including a removable window for using a polarization filter), which does not click in as nicely as on newer lenses but is more of a friction fit.

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Porst Color Reflex MC Auto (Cosinon) 55mm 1:1.4

Being a fan of the old Porst Color Reflex Auto 50mm 1:1.7 (M42) in both single- and multicoated versions, I could not pass up a deal for a really well-kept "Porst C-TL super" film SLR (apparently an all-black version of the Cosina Hi-Lite 405) with its matching 1.4/55 MC lens for less than the lens alone would be worth. Technically I need another film SLR just about as much as a hole in the head, but c'mon, complete with the original metal carrying chain and holster in good shape (hmm, could this be real leather after all? or just really good imitation?) and seemingly always kept under sane environmental conditions? The lens needed some cleaning up and has a few dust particles inside, but that's about it. S/N 10xxxx.

At the time (1975-ish), this all-metal black M42 1.4/55 with copious chrome trim and 7 elements in 5 groups was the fancier kit lens alternative to the aforementioned 1.7/50 (a 6/4). It's quite a chunky lens that's longer and stouter than any of my 50s (and not a lot slimmer than the Porst 28mm 2.8 MC auto F) at 66 mm dia. and 46 mm length from mount at infinity, features a 55mm filter thread and weighs in at 319 grams on the kitchen scale. My sample exhibits some play in its aperture ring that its lesser cousin did not have (which makes for a less classy impression than some of my other lenses even if it is functionally irrelevant). Otherwise it is quite similar, with a 0.5 m minimum focus distance, smallest aperture of f/16 (though its shape is a noticeably irregular hexagon starting from about f/5.6 on this sample), and half-stop clicks everywhere except between f/11 and f/16. I would not be one bit surprised if it were a close cousin to the Auto Rikenon 55mm f/1.4 (v3), which is very similar in size and weight and also features a flat rear element like a number of these "Tomioka" designs. Said rear element features a few minor chips on its fringe on my sample that it no doubt incurred when the lens was mounted or dismounted, so I recommend you focus it to about 0.8 meters before doing so in order to avoid damage.

I found light transmission to be average but acceptable, just beating out the newer PK mount Porst 50mm 1.7, as well as Chinon MC 50mm 1.7 and Auto Revuenon (Chinon) 50mm 1.4. That's certainly OK for this kind of lens and its vintage, though clearly not a patch on some newer designs like the XR Rikenon 50mm 1.4, which I may remind you was pretty much on par with the 50mm 1.7 cousin of this lens, and I would not be surprised to see something even newer like Rikenon P or Pentax-A or -F 50mm 1.4s do even better.

First test shots show a good amount of spherical aberration glow wide open that largely behaves itself by f/2, at least for objects in focus. This lens gets to a decent approximation of infinity on my K-x even at f/1.4, so that's good. Lateral CA shows to be well-controlled and quite inconspicuous, being yellowish-orange, and surprisingly longitudinal CA seems to be corrected very well, too, as I see none of the associated color oddities in bokeh wide open – not at all a given for a fast oldie lens. (And what do you know, the 1.7/50 counterpart is much the same. They really seem to have been designed along very similar guidelines, using computers I suppose.) The focus test shot also shows signs of spherical aberration overcorrection wide open, as there are double contours behind while bokeh in the front is smooth, but this reverses by the time you get to f/4. The "swirly" bokeh is a more common thing on old lenses, and if you look into the rear of the lens you can clearly see why, as you don't see the aperture reliably until about f/2.4, much like on the 1.7/50 – no problem on the newer Chinon 1.4/50 even at f/2, or the XR Rikenon for that matter.

The multilayer coatings of this lens look very similar to what's found on its 50mm 1.7 MC cousin, as you might expect. I was quite happy to have found this version given the reputation of lenses like this for flare sensitivity and contrast – they are clearly pushing the limits of single-coating. In fact, even this MC version remains quite flare-prone when a bright light source is in the frame (you can get some nice bluish image of the aperture when stopped down), and even outside you can still get some veiling flare not least because the front lens is far less recessed than on the 1.7. I found a typical "standard" rubber lens hood not to make much difference with regard to veiling flare, and on crop I would recommend something a good bit narrower / longer.

Given how many similarities I've found so far, a comparison to the 1.7/50 was pretty much unavoidable. In a nutshell, the 1.4 has less spherical aberration glow, less astigmatism and is sharper at f/2, and I think the outer areas still are a bit better by f/2.8, but beyond that it's pretty much a wash. At f/2, the 1.7 covers everything in some haze, while in the 1.4 at least the center portion of the frame looks acceptably contrasty. Neither is an "Art" series Sigma or Zeiss Distagon T* Otus, that's for sure, but then again it's been a few decades and that sort of glass is much bigger and weighs more than twice as much, not to mention the price. At the time, buying the 1.4/55 instead of the 1.7/50 bumped pricing of the entire camera from 629 to 729 DM (a factory worker might have made about 1200 a month). I imagine that pricing of this lens in today's money would be somewhere between the Samyang 1.4/50 and the "Art" series Sigma, akin to a typical Pentax Limited.

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SMC Pentax (K) 135mm 1:3.5

I felt like I still hadn't found the perfect 135 lens yet, so I took a bit of a gamble on a very meagerly-described specimen of this generally well-liked lens (more so than the M series part, which seems to be enjoyed more for its extraordinary compactness than outstanding optical performance). Turns out it's missing the white plastic bump and the front and back elements were dusty / filthy (it didn't come with a back lens cap and had presumably been stored upside down), but other than that it's in pretty good shape. Some isopropyl alcohol and cotton swabs took care of the filth to a satisfying degree, although it be mentioned that the back element is very deeply recessed and behind a rectangular aperture, so it's a bit of a bear to clean.

At a whopping 88 mm from mount, you could say this guy is about a head taller than your average 135 (Zebra Sonnar: ~85, Porst MC: ~83, AGFA/Chinon MC: ~78, RMC Tokina: ~75, and the M 135 at 63 can only be called petite), though its diameter of 63 mm with 52 mm filter thread is nothing unusual, and at 364 grams it's clearly on the lighter side, too. Actually its dimensions are quite similar to the f/2.5 part, which is 2 mm shorter and 3 mm stouter but obviously much heavier. And that's not even including an integrated lens hood, as this was a clip-on type. That said, the front element is noticeably recessed, similar to the Sonnar. Despite the length, minimum focus distance only extends to 1.5 meters, which is a typical value for an old 135 (save for the Sonnar), but not exactly earth-shattering these days.

Optically, the K 135mm 3.5 employs 4 elements in 4 groups … it's sort of a dissolved Sonnar (which had two cemented elements) with a fair bit less glass. At least three of these appear to be SMC coated, save for possibly the second front element – still a better stat than any of my other 135s.

In transmission testing, the lens propelled itself into the top group, being nigh indistinguishable from the A 50mm 1.7. That's an excellent result for a lens made in the mid-'70s. (In fact, the same seems to apply to the even older SMC Takumar.)

On-camera testing was conducted using my new (used) K-50.

Wide open, you can see some spherical aberration haze, and the corners still are a bit on the fuzzy side, but overall nothing terrible. One step further down (f/4.5-ish?), things have improved significantly, and by f/5.6 it's just the corners that remain a bit fuzzy, and elsewhere things are really getting quite sharp indeed. By f/8, sharpness is good across most of the frame, delivering much better results in the outer areas than the RMC Tokina, which is getting rather fuzzy there. All this despite infinity focus seeming a hair short of what it should be. In the center, both are sharp enough to outresolve the 16 megapixel sensor and give demosaicing some funny ideas.

I found some lateral CA on a rather typical non-dramatic level, similar to the RMC Tokina. In my f/8 test shots, I applied -13 to red in the K lens shot in Digital Camera Utility 5, as opposed to -12 (red) / +3 (blue) in the Tokina. That said, longitudinal CA does not appear to be entirely corrected even at this point, and I saw some red fringes in front of the focal plane that were, at the very least, much less pronounced in the Tokina. That's probably down to the age of this design, which I assume is identical to the Super Takumar and SMC Takumar versions, and those have been around since the late '60s / early '70s.

Without a built-in lens hood, propensity to veiling flare is rather high (as that is caused by light hitting the surfaces at a very low angle, rendering coatings largely ineffective). I found that on crop, a lens hood can be surprisingly long before it causes vignetting (I literally got to 10-15 cm or so), and have been considering stacking two screw-in threaded tele lens hoods.

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135mm Shootout (2): Internal Reflections (Primes and Zooms)

There is a fair bit you can learn about lenses by just looking at them. One prime example would have to be the topic of internal reflections. It takes little more than a lamp in a room to tell how the lens is going to perform under adverse lighting conditions (sun outside the frame but still not that far away) once you have a decent idea of what to look for. Simply look in from behind, providing shade if necessary, and spot reflections depending on where the lens is aimed at. Since I just got my shipment of assorted screw-in lens hoods in, I thought I'd do just that.

Before we get started though, I'll hit you over the head with one conclusion already:
Integrated lens hoods on 135s are a nice touch, but nowhere near sufficient. Not anywhere close. They may help with some use cases like the sun being pretty much overhead, but still leave plenty of room for it to get into the lens. In my tests, they basically made no difference. No surprise really, they tend to provide a length of maybe 15 mm, which is awfully short for a tele lens hood. In testing with a Pentax K 135mm f/3.5, I found that lengths up to 10…15 cm would be acceptable, at least on crop… up to a factor of 10 more.

Folklore has it that a good lens hood can work wonders for contrast, and I can't say I'm surprised after what I found. There's always some sort of internal reflections to be seen when the lens is confronted with strong light sources somewhat outside its field of view, most of all when wide open.

First off, the Porst Tele MC 1:2.8 135mm auto D. This lens has its share of issues with blackening, with a thin ring of shiny bare metal being visible somewhere between the front elements and a smooth and shiny black surface around and behind the rear element. Barefoot, it takes stopping down to about f/13 to f/16 until all the reflections around the rear element have disappeared. The built-in hood makes zero difference. Add an 58 mm dia., 35 mm long screw-in hood, and things improve quite a bit, with this threshold moving to about f/11. Add another 62 mm dia., 35 mm long hood in front, and we're at f/8. Still not great, but it is near bulletproof at this point. Quite clearly, this guy will pretty much appreciate the longest / narrowest hood you can throw at it without provoking vignetting. It'll never be the most contrasty wide open though.

Next up, the Pentax K 135mm f/3.5. This lens has good internal blackening and is never by any means terrible. There are some reflections around the perimeter of the last element and the rear flange following it. These clear up by about f/8 to f/9.5. Add one lens hood, and we're closer to f/6.7, add both and f/5.6 it is until the reflection around the last element vanishes. The rear flange reflections prove harder to extinguish completely, however, and further improvements can be had up to about f/9.5.

Now the RMC Tokina 135mm f/2.8 "hand grenade". Oh dear. While internal blackening is basically good and the reflection around the back element remains the only issue beyond f/4, this takes an inordinate amount of stopping down to clear up. Basically it's OK at f/16 or f/22, but who uses those on a regular basis? We gain maybe a stop with one hood, and another with both, but f/11 still isn't awe-inspiring. This lens used to strike me as low on contrast, now I'm not surprised. The rather reflective back element definitely is not helping matters either.

The AGFA / Chinon counterpart, another lens with good internal blackening, behaves similarly but a bit better. I'd be fine with f/16 barefoot and f/8 with both hoods in, with f/11 then qualifying as bulletproof.

The CZJ Zebra Sonnar does better than it has any right to, being a single-coated lens with shiny metal aperture blades (though internal blackening is very good otherwise). Barefoot, stopping down to f/6.7 leaves nothing but some minor rear flange reflections. Add one hood, and f/5.6 will do. Add both, and we're basically there at f/4.5. Phenomenal. You just don't want the sun actually in the frame, this it does not like (expectedly).

The RMC Tokina 75-150 f/3.8 surprisingly has me a lot more convinced than its fixed focal cousin while behaving similarly. It's pretty much bulletproof at f/16 even with no hood, improving to f/11 with two, with f/8 still being only marginally more critical and just fine most of the time.

The Pentax-M 80-200 f/4.5 is another rather well-behaved lens. At the short end there are very few issues even wide open (and the built-in hood with its ~18 mm extension helps), but things progressively worsen as you zoom in, and you get some reflections around an internal element and the last one. You can also see part of the helicoid and some thread then that are reasonably reflective, I am guessing those may be involved.
At 135, stopping down to f/8 will eliminate the last element fringe reflections, it's hard to get rid of the flange reflection entirely though. Adding one 35 mm hood essentially eliminates last element reflections and a fair bit of the flange reflections as well. Things improve further with the second hood (total: 70 mm length, 62 mm opening), and there should be very few problems even wide open, I find it very hard to provoke any secondary reflections at this point. By f/6.7 it's basically pitch black around the aperture no matter what you do.
Getting 200 mm to the same level would require extending the hood yet again, for a total of 3 segments.

The Sigma 55-200 DC only exhibits minor reflection around the back element, though getting rid of it entirely involves stopping far down, and a hood won't help an awful lot, though it does keep light bouncing around the front element out. Even the effect of my two hood combined is just noticeable but hardly earth-shattering.

The Sigma 70-210mm UC Zoom behaves very similarly on the whole, with the front element being less of an issue but three low-level fringe reflections occurring which are very hard to get rid of entirely, with a hood making little difference.

My trusty Sigma 70-300 DG OS again is another typical modern-day Sigma in that it only exhibits low-level reflections to begin with, but arguably better than the other two because it only does so under specific angles. Entirely getting rid of them will require stopping far down though (again), wouldn't be surprised if that were f/16 to f/22. It's very hard to get it bulletproof the way the old M 80-200 is with both hoods at f/6.7, though a long hood would help.

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More Internal Reflection and Hood Testing: 50-55 mm

I now have two stages of circular screw-in lens hoods available:

35 mm length, 58 mm front filter thread, for 49, 52 and 55 mm
plus another 35 mm length, 62 mm front filter thread, for 58 mm, giving me 70 mm extension in total.

I find that a 35mm lens can easily take stage 1 but two is too much. There still is some vignetting in the corners with 50s and 55s at large apertures, but it's gone by f/2.8. As you can probably infer from this, your average 135 could take something much longer still.

After my look at 135 mm, I decided to grab some of my 50s and 55s. They all behave in rather similar ways, with light mainly seeping out around the perimeter of the last element, though they vary in how severe it is and to what degree it can be cleaned up.

Porst (Cosinon) 55mm 1.4 MC: Oh dear. I know it's an older lens design, but this guy needs a hood, badly. Even then, it is about bulletproof only by f/16 and close at f/11. Extending the hood once more, it gets pretty good at f/4 and bulletproof at f/5.6, with only minor, direction independent fringe reflections remaining that should not be disturbing (but I may remind you that stopping down to about f/2.8 is required to eliminate vignetting). Wide open, there is an additional fringe reflection at an internal element, though that is covered up by f/1.8.

Porst Color Reflex (MC) Auto 50mm 1:1.7 (M42): Both the MC and non-MC versions of this lens perform just about identically here, and, perhaps owing to the recessed front element, results are a good deal less disconcerting. With one hood, it's not too bad by f/2 (there is another internal fringle reflection wide open), quite commonly good at f/2.8, better at f/4 and bulletproof at f/5.6. You can get one stop more out of it when adding another segment, but do remember that there is vignetting near full aperture. It is a bit disappointing to note essentially no effect of the multicoating – seriously, I have a really hard time keeping the two versions apart.

The slightly newer version of this lens with essentially the same optics but a less recessed front element performs similarly but unsurprisingly could use a longer hood, reaching bulletproof level with one hood segment only at f/8. That's the effect of a measly 5 mm difference in barrel length!

The Rikenon P 50mm 1:1.7 is doing OK. Once I add one stage of hood, it's good at f/4 and bulletproof at f/5.6. (With the JJC universal bayonet hood, it's largely bulletproof by f/8.) The old Porst 50/1.7 still seems a bit better at f/2.8, possibly the more recessed front element at play again.

Demonstrating that f/1.4s don't have to be that bad is the XR Rikenon 50mm 1:1.4. Even without a hood, it's not too bad at f/8 and essentially bulletproof at f/16. Adding a hood makes it quite good by f/4 and bulletproof by f/5.6. With two (again: vignetting) it's bulletproof by f/4 and close at f/2.8.

The Auto Revuenon (Chinon) 50mm 1.4 kit lens finds itself about on XR Rikenon level without a hood – not too bad at f/8 and bulletproof at f/16. Adding a hood, it's pretty good by f/4 and just about bulletproof by f/5.6.

The PK mount Porst 50/1.7 may be a smidgen behind the others, reaching bulletproof level with a hood by about f/6.7. This sample is also slightly hampered by haze on one of the back elements.

My poor unfortunate misassembled PK mount Porst Color Reflex MC Auto 50/1.4 (another 1978-ish Cosinon) cannot be made bulletproof without a hood. Add one, however, and it's perfect at f/8 and close at f/5.6. Another segment (never minding the vignetting wide open) brings this to f/4 and f/2.8, respectively. So neither great nor terrible.

The A 50/1.7 needs a hood but does quite decently, reaching bulletproof level by about f/6.7 then. f/5.6 is close and f/4 still generally very good, f/2.8 still is decent, and even wide open it should do well when kept away from light sources. That's Pentax for ya. I still hate that bloody aperture ring though.

I'd call the M 50/1.7 bulletproof by f/9.5 even without a hood, and adding one pushes that to f/4.5. f/2.8 still is very good, and again blackening seems good enough to risk using it wide open, maybe when kept somewhat away from light sources. (I'd say the first intermediate step at f/2.5-ish still fares better than the non-MC Porst Color Reflex Auto at f/3.3.) Surprisingly, these results are rather better than those for the A series part (which does well wide open but then needs a while to get to perfect level), putting the M 50/1.7 at the top of the heap.

My Chinon 50/1.7 MC with the terribly oily aperture (ewww) is better than I first thought – aperture readout on this guy is iffy to say the least. It reaches bulletproof level with a hood by about f/4.5 (without a hood, it's pretty good but not perfect by f/11). It's combating some haze, no surprise given its condition.

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Sigma 17-50mm 1:2.8 EX DC HSM

I've had my eye on this lens for a while. You see, there's plenty of opportunities where you just want a decently versatile standard zoom, e.g. since you just don't get the time to swap lenses. Besides, I haven't been too convinced by the sub-35mm lenses I've run across… if you want something good as in better than the trusty 18-55 kit, even the vintage ones aren't cheap either. I was shying away from the Tamron 17-50 2.8 which has a reputation for being flimsy, while the Sigma counterpart appears to be more robust and seemed to be a good performer, though there were multiple reports that a visit to Sigma service may be needed to sort out focusing issues. I was originally going to buy one new (a little over 300€ isn't a bad price for a lens like this) but eventually got a used one for roughly half new price. Not complaining. Even if a Pentax 16-85 would fare better, it's almost 4 times as much, and I'm not using my camera that much either.

The Sigma 17-50 2.8 EX DC HSM is a reasonably chunky zoom lens weighing in at 558 grams w/o or 585 grams with the supplied petal lens hood, with a whopping 77 mm filter thread on the front element (thank goodness I'm not much of a filter guy). That's a far cry from the 18-55 kit, let alone the DA 35 f/2.4, and actually bigger than a Pentax 16-85 3.5-5.6 (448 g, 72 mm), but then of course this is an f/2.8 we are talking about. I'm not normally too much into heavy lenses (I wish they'd make a good compact 135mm f/3.5-ish again that's not as optically meh as the old Pentax-M), but I mean, some others on my list of lenses to check out are the Samyang 16mm f/2 (just about same size) and 135mm f/2 (even heavier), so there. Anyway, back to the lens. Fit and finish actually remind me a lot of the 70-300 DG OS I already have, fancy gold trim ring aside (which is pretty much only visible sideways in order not to reduce the stealth factor). The lens cap supplied has been described as "flimsy" but in my opinion gets the job done just fine. A nice leatherette carrying case is also supplied but I'm not going to use that.

In terms of features, you can lock zooming at 17 mm in order to avoid zoom creep (of which my sample thankfully exhibits very little), and since this lens employs an internal AF motor, there's another lever to switch to manual focusing. The manual focus ring has a decent width to it, though focus throw isn't exactly super long at about 30° (if that). Mine is the newer version without OS – while a stabilizer is welcome on a tele, on a normal zoom it mainly saps your batteries dry while not being an awful lot better than modern-day sensor-based shake reduction (and my K-50 should be pretty good at that).

Handling wise, yes, the combination with my (Eneloop-powered) K-50 is getting a tad heavy, though not as cumbersome as with the 70-300 DG OS, which can get a lot longer towards the tele end and in fact exceeds the length of this lens at all times. Autofocus is fairly quiet and quick. The front element does not rotate on focusing though it does (a bit) on zooming.

Optically, the lens employs no less than 17 elements in 13 groups, which is quite an impressive number. On these you'll find modern-day multilayer coatings as you'd expect, mostly greenish but also brownish looking. Their performance appears to be good but reduces at increasing incident angles, again as usual. Internal blackening thankfully does very well from about 35 mm up, though the wide end does not fare so well, especially at the larger apertures, even if the hood helps somewhat. The lens has been noted to be somewhat susceptible to discrete flares, so I guess that's where those come from.

For such a complex lens, transmission actually turns out to be really good with just a moderate amount of yellowish cast, slotting in alongside the 6/4 Porst (Cosinon) 50mm 1.7 MC and its ilk. A number of other modern-day zooms manage to sneak past thanks to being substantially less complex, but even then the difference isn't big.
An estimated 0.25 Tstops worth of loss means at least a 99.34% transmission (less than 0.66% of reflection) on each of the 26 glass-air surfaces, discounting the cemented ones and any cement and glass losses. Attributing maybe 0.1 Tstops to the latter means less than 0.4% of reflection. Yay for modern coatings, I say. Attempting an exercise like this without any coatings at all would result in a loss of about 1.5 stops (not to mention that contrast would be plain terrible with all of the stray light bouncing around inside the lens – there's a reason why pre-war lens designs tend not to have more than 3 groups, from Cooke triplets over the classic Zeiss Tessar up to adventurous designs like the f/1.5 Sonnar sporting two groups of three cemented elements each, seemingly a pain to manufacture).

There is a bit of barrel play, but it appears to be as well-controlled as in any of my zoom lenses, including the Tokina AT-X. The Pentax 16-45 is particularly notorious for this (the one I have in fact is pretty wobbly and unsurprisingly has pretty bad corners on the wide end, where it is the longest) – the 18-55 isn't really any better but its extension is an awful lot smaller, making it less of an issue. The 70-300 DG OS was quite good already, this 17-50 arguably is even better.

- To be continued -

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Adventures in Pentaxland

What you'll find on this page

Camera notes

General lens articles

Lens notes

Zooms, normal and wideangle

Zooms, tele

Primes, normal

Primes, wideangle

Primes, tele

Camera notes

Pentax K-5

Pentax K-x

Chinon CP-7m

Porst compact reflex C-TL super (Cosina Hi-Lite 405 version)

Lens notes

DA L 18-55mm 1:3.5-5.6 AL

RMC Tokina 75-150mm 1:3.8

Rikenon P 50mm 1:1.7

Sigma 70-300mm 1:4-5.6 DG OS

RMC Tokina 135mm 1:2.8

Pentax-M 80-200mm 1:4.5

Tokina AT-X 28-85mm 1:3.5-4.5 (older version)

XR Rikenon 50mm 1:1.4

SMC Pentax-M 28mm 1:3.5

Auto Revuenon MC 50mm 1:1.4 (6-blade aperture)

Porst 28mm 1:2.8 MC auto F

Vivitar 28mm 1:2.8 MC (K03)

AGFA COLOR (Chinon) 28mm 1:2.8 Multicoated

AGFA COLOR (Chinon) 135mm 1:2.8 Multicoated

Summing up: Old MF lenses

SMC Pentax-M 50mm 1:1.7

Porst Color Reflex Auto 50mm 1:1.7 (M42)

Revuenon MC Macro 70-210mm 1:2.8-4

Light transmission ranking of my lenses

SMC Pentax-A 50mm 1:1.7

Porst Tele MC 135mm 1:2.8 auto D (ø55) / 135mm shootout

28mm indoor shootout

The candidates

Wide open: f/2.8

Wide open: f/3.5 – f/4.0

General observations

Sigma UC Zoom 70-210mm 1:4-5.6 AF

Alfo Supercolor mc Auto 28mm 1:2.8

On "overspec'd" lenses

Auto Revuenon (Chinon) MC 35mm 1:2.8

Porst Color Reflex MC Auto 50mm 1:1.7 (PK)

Porst Super-WW-AS MC G 28mm 1:2.8

How to remove the "AS" mount adapter

Lens Coatings: The Fine Print

Porst Color Reflex MC Auto 50mm 1:1.7 (M42)

Sigma 55-200 1:4-5.6 DC

Pentax DA 55-300mm 1:4-5.8 ED

Pentax-M 35mm 1:2.8

Auto Revuenon (Cimko) multi coated 35mm 1:2.8

Carl Zeiss Jena "Zebra" Sonnar 3,5/135

HD Pentax DA 16-85mm 1:3.5-5.6 ED DC WR

Pentax DA 35mm 1:2.4 AL

Pentax DA 16-45mm 1:4 ED AL

Porst Color Reflex MC Auto (Cosinon) 55mm 1:1.4

SMC Pentax (K) 135mm 1:3.5

135mm Shootout (2): Internal Reflections (Primes and Zooms)

More Internal Reflection and Hood Testing: 50-55 mm

Sigma 17-50mm 1:2.8 EX DC HSM