[ChristianRock]

The K Series was introduced in June 1975 and the M Series a year later in 1976. The K Series had the same SMC coating that were on the late SMC Takumar lenses, but on more optical surfaces. That's the only difference between the late Takumars, K and M series lenses. The M Series lenses started to come out only a year after the K Series were release, so Pentax did not change anything coating wise in that period. The only new feature with the M Series lenses were the smaller size.

Phil.

From what I can tell, the SMC coatings were changing and constantly evolving, and that can be seen by looking at the colors in the reflections. K-era lenses have a more yellowish/orange dominant reflection, and M-era starts to get a bit more bluish/purple, something that increases in the A series.

It gets a bit more confusing as some lenses like the K 50mm f/1.2 had two distinct versions, one for the K and one for the M era. The K 24mm f/2.8 was created during the M era so it's not a "true K era" lens - and it will have M era coatings.

It can be even more confusing as I've seen M era K 50mm f/1.2 lenses that were not as bluish/purple as others, yet also not as yellow/orange as earlier K 50 1.2 examples.

SMC was just the name for multi-coatings. The formula itself evolved and was getting better and better through the years.

Here's a K era 50mm f/1.2:


Here's the M era 50mm f/1.2, which is the one I have. Notice how the lettering changed, it is truly a "V2" version of the lens.

[gofour3]

From what I can tell, the SMC coatings were changing and constantly evolving

Perhaps in the 1980's after the A Series lenses were released but not in the K-M Series. I got my first K Series lenses in 1975 and have all the brochures from that period, they (Pentax) mention the extra SMC coatings on the K Series lenses and there is nothing different in the brochures during the rest of the 1970's to 1983 when the A Series first appeared. The SMC technology was a big deal back then, and Pentax would have updated their brochures if they "improved" it in any whey . A SMC "update" that would improve optics after just one year between the K and M Series, is highly unlikely.

Correct Pentax did change the lens name (adding mm) and lettering on lenses in 1976 and that's well documented. All M Series lenses have the new format and the existing K Series lenses that were not discontinued were updated as well. So yes you will have numerous K Series lenses with an early and late name.


Phil.

[photogem]

Are you sure? SMC coatings have changed quite a bit throughout the years and even more so during these earlier years. Is there a place where you can find information to confirm this, or have you opened both up?

It is indeed so.
The first coatings were the S-M-C Super Multi Coating on Pre SMC Takumars and had 7 coatings
It was a complex story because

Then came SMC with 9 coatings

Then came Ghostless


I might write something more about this because the history is very interesting.
Zeiss was involved, an Italian bastard lying about the impossibility of 7 coatings but correcting his claim by claiming Fujifilm did 11 coatings
which they didn't of lenses for cameras until later on.

[ChristianRock]

It is indeed so.
The first coatings were the S-M-C Super Multi Coating on Pre SMC Takumars and had 7 coatings
It was a complex story because

Then came SMC with 9 coatings

Then came Ghostless


I might write something more about this because the history is very interesting.
Zeiss was involved, an Italian bastard lying about the impossibility of 7 coatings but correcting his claim by claiming Fujifilm did 11 coatings
which they didn't of lenses for cameras until later on.

I'm not talking about major things, like the number of coatings or the introduction of ghostless and SP coating... I'm talking about perfecting the coatings that they were using.. I have been told they changed the formulas through the years.

You have to at least concede that the reflections look different between typical K and M lenses. Also, my experience having had a few K and M lenses is that the M control flare a bit better and have a bit more contrast than the Ks.

I wish I could locate an interview with an Asahi engineer back in the day that said they had been constantly working on improving the SMC coatings through the years.

[northcoastgreg]

I have been told they changed the formulas through the years.

I'm not sure it's as much as case of changing the formulas as fine tuning the coatings. Beginning at least with the A series of lens, an effort was made to produce consistency of color rendering throughout the entire series (something which is largely missing from the original K series). That required custom making the coatings for each lens so that it produce similar color output to all the A series lenses. I haven't come across any evidence that this made the lenses more flare resistant. I don't think we see that until the introduction of ghostless coatings in the late nineties.

[ChristianRock]

I'm not sure it's as much as case of changing the formulas as fine tuning the coatings. Beginning at least with the A series of lens, an effort was made to produce consistency of color rendering throughout the entire series (something which is largely missing from the original K series). That required custom making the coatings for each lens so that it produce similar color output to all the A series lenses. I haven't come across any evidence that this made the lenses more flare resistant. I don't think we see that until the introduction of ghostless coatings in the late nineties.

Yeah I think I used the wrong word, English is my 3rd language. I didn't mean formulas as in the number of coatings or anything major, but the chemical formulas applied. Fine tuning the coatings would have been a better way to express it, thank you for that correction....

My experience is that the newer the series, the better the flare control was getting, but this also had to do with the optical glass formulas and the internal components, not just the coatings...

[photogem]

I'm not talking about major things, like the number of coatings or the introduction of ghostless and SP coating... I'm talking about perfecting the coatings that they were using.. I have been told they changed the formulas through the years.

You have to at least concede that the reflections look different between typical K and M lenses. Also, my experience having had a few K and M lenses is that the M control flare a bit better and have a bit more contrast than the Ks.

I wish I could locate an interview with an Asahi engineer back in the day that said they had been constantly working on improving the SMC coatings through the years.

I guess you are right with this and yes, I wish I would have written down material I got from talks with engineers, I recall particular one with an Asahi engineer when we spoke about the FA31ltd and how difficult it was to adjust it, how easy it could go out of alignement and that such slight misalignements produced a certain softness which for some became that very pixie-dust when using that lens wide open. It was also him who told me that the DA16-45 was based on a similar design but as much complicated to align.

[Mercifulfate]

Reading these three lens reviews (and looking at lots of photos taken using these lenses), I have some questions, hoping you all can shed some light:

* S-M-C/Super Macro-Takumar 50mm F4 Reviews - M42 Screwmount Normal Primes - Pentax Lens Reviews & Lens Database (looking only at the S-M-C version)
* SMC Pentax 50mm F4 Macro Reviews - K Prime Lenses - Pentax Lens Reviews & Lens Database
* SMC Pentax-M 50mm F4 Macro Reviews - M Prime Lenses - Pentax Lens Reviews & Lens Database

In general, and in particular for these three lenses, are there actual optical differences between Pentax lenses that are listed (or seem to be) versions of previous lenses? In other words, if the optical diagram is the same, is the actual glass/spacing/care in manufacture/etc also the same? Are there practical differences (beyond copy-to-copy variation) in sharpness/bokeh/aberrations/vignetting/ability to focus at infinity/etc?

Also, what physically differentiates Takumar, K, and M lenses, meaning things like materials, durability, problems with older vs newer versions (eg brittle plastic, frozen aperture rings, oil on blades, etc), ease of manual focusing, and so on?

The K version says it was "succeeded by an M version". I don't see any indication in the review page that the Takumar is a prior version of the K/M lenses, but the optical diagram looks the same: 4 elements, 3 groups.

All three lenses have the same min/max aperture, min focus distance, and max magnification, but differ in weight and size:

SMC Takumar: filter size: 49mm; diam x length: 57 x 54mm; weight: 248g.
SMC Pentax K: filter size: 52mm; diam x length: 63 x 54mm; weight: 241g.
SMC Pentax M: filter size: 49mm; diam x length: 63 x 42.5mm; weight: 160g.

Here is the question that prompted all my other questions: How can the M version be the same optically as the prior two lenses if its 12mm shorter and 80g lighter? Does it somehow use smaller/lighter lens elements?

I hit the "buy" button for a used copy of the "M" version (hasn't gotten here yet), so I'm probably having buyer's remorse before even setting eyes on it. Sigh.

All great lenses but you are not going to get true 1:1 magnification unless you use the Macro Takumar or find a SMC Pentax-FA 50mm F2.8 Macro which also has 1:1. The FA rarely leaves the mount on my K-1.

[eles]

This page has some interesting details about Takumar build and optical quality, that forum members might find interesting if they haven't already seen it: Pentax Super-Takumar 24mm f/3.5 SM - of course I'm in no position to judge how accurate the information is.

All great lenses but you are not going to get true 1:1 magnification unless you use the Macro Takumar or find a SMC Pentax-FA 50mm F2.8 Macro which also has 1:1. The FA rarely leaves the mount on my K-1.

You really can't go wrong with any macro lens --- they're all very good. I would generally prefer an SMC coated lens, all else equal, but the other issue here is the 1:2 magnification of all K and M series macros and of most of Taks. The one exception is an old "macro-Takumar" from the mid-sixties, which is 1:1. For those shooting APS-C, 1:2 may not be that big a deal, but I've found 1:2 does not always provide enough magnification on FF.

I am, or rather was, somewhat trying to find Pentax replacements for a Nikon lens, the Micro-Nikkor 55mm f2.8 AIS, which has 0.5 magnification. I considered leitaxing this lens to use on the Pentax K-1, but we still have the (good working condition) Nikon FE camera it was purchased with, back in the middle 80s. I used this lens mostly as a general purpose "always on the camera" lens, but also enjoyed using it to photograph various things close up.

Replacing the Micro-Nikkor is doubly difficult because I used it first on a Canon APS-C digital camera, with the resulting "effectively 85ish mm" equivalent field of view; and then on a Sony A7 full-frame digital camera, via adapters. I really liked the field of view on the APS-C, including as a portrait lens, so I thought the 77mm Pentax limited (which I recently bought used) would fill the role of "55mm micro-nikkor on APS-C".

It turns out that however excellent the 77mm Limited is in most respects, it has a rather noticeable problem with "bokeh fringing/spherochromatism/secondary longitudinal chromatic aberration", which apparently is to be expected with wide-aperture lenses (Lens Rentals | Blog). The first random test picture I took with the 77mm limited could be used as the "poster child" example of spherochromatism. The Micro-Nikkor doesn't have this characteristic.

So I spent some time perusing Cicala's excellent discussions of lens types and history of lenses, trying to learn a bit about lenses that can be made without spherochromatism. Along the way I saw a diagram for a Tessar lens and recognized it as being the same optical design as the Pentax 50mm F4 lenses. Perusing flickr examples of images taken with these 50mm F4 macro lenses, I couldn't find any spherochromatism (it was easy to find examples in images taken with the 77mm limited). Plus the bokeh from the 50mm F4 seems always pretty (I do like the Micro-Nikkor bokeh) and under the right circumstances somehow rather appealingly different from the Nikon lens. So I'm no longer trying to replace the Micro-Nikkor, the 50mm F4 macro is something different. Though hopefully it will be more or less equally "flat field", lacking distortion, and such.


The lens might arrive today, excitement builds!

[northcoastgreg]

It turns out that however excellent the 77mm Limited is in most respects, it has a rather noticeable problem with "bokeh fringing/spherochromatism/secondary longitudinal chromatic aberration"

I've heard about the 77mm bokeh fringing, but in images I've only seen very faint traces of it. The bokeh fringing of the K 50/1.2 can be much worse.

So I'm no longer trying to replace the Micro-Nikkor, the 50mm F4 macro is something different.

Yes, I would expect it to be different — reflecting the company's different lens design philosophies, with Nikon being more in the tradition of Zeiss lenses, and Pentax more in that of Leica.

[eles]

Yes, I would expect it to be different — reflecting the company's different lens design philosophies, with Nikon being more in the tradition of Zeiss lenses, and Pentax more in that of Leica.

Hmm, that's very interesting. Until you mentioned it, I hadn't heard of Zeiss and Leica differing lens design philosophies. But doing a quick internet search shows there is quite the discussion though perhaps with "more heat than light".

Do you have any thoughts on how differences "way back in the beginning" or "40 years ago" or even "right now" might play out in practical terms, meaning things like "this lens design trades this aberration for this other positive quality", and so forth?

Conforming with your mention of "Zeiss philosophy lenses", until getting my K1 camera maybe two/thirds of my photographs were taken with the Micro-Nikkor 55mm lens. Most of the rest were taken with a Zeiss-Distagon T 28mm F2.8 C/Y mount "green M" lens, circa mid-eighties vintage like the Nikon lens, that I got shortly after getting my first DSLR. I liked both lenses quite a lot and so never had reason to think about lens design or what might make one lens different from another.

[northcoastgreg]

Do you have any thoughts on how differences "way back in the beginning" or "40 years ago" or even "right now" might play out in practical terms

Well of course all these differences are pretty darn subtle. Both Leica and Zeiss make great lenses, and the best lenses from Nikon and Pentax, although not quite matching the German lens makers, come reasonably close. With Leica there was a bit more emphasis on rendering — the so-called "Leica look." Zeiss emphasized sharpness and contrast. The Pentax lens engineers supposedly worshipped Leica, but they didn't slavishly try to reproduce the Leica look. They developed their own ideas of what rendering meant, and that evolved over the years until you get to the Pentax "limited" lenses, which were designed based on the perceptual analysis of images, rather than exclusively or largely on ultra complex designs via computers. Pentax was so proud of their first limited lens, the FA 43/1.9, that they produced a special limited edition for the Leica M mount.

Pentax incidentally also has a connection to Zeiss through their coating technology. Zeiss developed the first anti-reflective coating (I believe back in the thirties) and Pentax invented a relatively inexpensive process for applying multiple coatings on glass. In return for access to the Pentax technology, Zeiss designed a couple of Pentax lenses back in the seventies. So in a sense you could say that Pentax was inspired with their focus on "rendering" by Leica, and their coating technology (which inspired Pentax's emphasis on color rendering) from Zeiss.

[photogem]

With Leica there was a bit more emphasis on rendering — the so-called "Leica look." Zeiss emphasized sharpness and contrast. The Pentax lens engineers supposedly worshipped Leica, but they didn't slavishly try to reproduce the Leica look.

That is too simple. There was and partly still is a history of a deep respect of the Japanese towards vintage masterwork.
One can find that particular strong in High-End Audio and especially with tube-equipment (Shindo for example, but there are actually many more).

But you are very correct, the Japanese never copied but mastered it to a point never reached by others. The Koreans tried and very few (mostly unknown outside the country) came close but the mastery the Japanese reached was unsurpased.
There is of course the strange history and the connection of Japan with Germany before and during WWII.

Pentax incidentally also has a connection to Zeiss through their coating technology. Zeiss developed the first anti-reflective coating
(I believe back in the thirties) and Pentax invented a relatively inexpensive process for applying multiple coatings on glass. In return for access to the Pentax technology, Zeiss designed a couple of Pentax lenses back in the seventies. So in a sense you could say that Pentax was inspired with their focus on "rendering" by Leica, and their coating technology (which inspired Pentax's emphasis on color rendering) from Zeiss.

After WWII Germany lost the right to all patents. Zeiss had patents but lost them as well of course. So they had to find new contacts.
The contact with Pentax was based only that and didn't last long. The great modern T* coatings of Zeiss came much later of course and are fantastic.
Nevertheless I found the Non-AF lenses available for Pentax too heavy plus I need AF due to eyesight. But they

But I loved the rendering, contrast and micro-contrast. Something very special. But also very expensive.
Leica is way way too expensive.

[stevebrot]

I've heard about the 77mm bokeh fringing, but in images I've only seen very faint traces of it.

Ditto, significant PF secondary to LoCA requires some effort to generate in actual practice.


Steve

[stevebrot]

This page has some interesting details about Takumar build and optical quality, that forum members might find interesting if they haven't already seen it: Pentax Super-Takumar 24mm f/3.5 SM - of course I'm in no position to judge how accurate the information is.

That lens is reviewed on this site and is well-respected.

S-M-C/Super Takumar 24mm F3.5 Reviews - M42 Screwmount Extreme Wide-Angle Primes - Pentax Lens Reviews & Lens Database

Whether it should be preferred over the optically identical Pentax-K 24/3.5 or other Pentax K-mount options for 24mm is hard to say. Ditto for well-respected third-party options at 24mm (e.g. Sigma Super-Wide 24s, Tamron 24/2.5 (01B/01BB). Kiron 24/2.0).


Steve