[mtgmansf]

Who are these re-coaters you found on google? Please share you findings so we can help you evaluate. Guessing that only the best lenses for film, video, and stills would be worthwhile, but who knows?

[ChrisPlatt]

The Takumar bayonet series lenses were budget models.

SMC Pentax lenses multicoating is excellent even by today's standards.

Why not simply trade up? It would probably be less costly.

Chris

[leekil]

The bayonet lenses are multicoated, they are just not SMC. They already potentially outperform their equivalent lenses, and it largely depends on copy variation.

Is there evidence they outperform the SMC lenses, or are you just saying "the Taks are fine, why bother with trying to get better"?

[ZombieArmy]

Is there evidence they outperform the SMC lenses, or are you just saying "the Taks are fine, why bother with trying to get better"?

GUB did a test and shows it outperforms the M/K/Takumar lenses. It could probably only match the A series since it's the same design.

[Dartmoor Dave]

Some people prefer the rendering style of the bayonet Takumars over the SMC equivalents. I certainly do. Back when I still owned my M series 28mm/2.8 I compared it against a friend's bayonet Takumar 28mm/2.8, and we were both astonished to find that we preferred the Tak's rendering by far. It was what convinced me to get rid of the last of the M and K series lenses that I owned.

[stevebrot]

I wasn't talking about the value. I was talking about seeing this from the perspective of an experiment.

If you have the money to burn, then go for it. The cost will be several hundred dollars. Remember too, that the difference between the Takumar Bayonet and their SMC cousins is more than just the coatings (single vs. smc). Edit: I badly mispoke in that at least the optical formula for the M/A 28/2.8 and A 135/2.8 are the same as for the Takumar Bayonet equivalents. It is known that the Takumar Bayonet lenses were made by Pentax's CPC subsidiary, but not known whether all of the lenses in question (SMC and CPC) were made on the same assembly lines.

And besides, samyang uses cheap plastic for most of it's budget lenses.

Truly? The ones I have used and handled are mostly metal.


Steve

[stevebrot]

Yes it's readily available! Just search on Google!

It is customary when reporting on an online resource to provide a link. Just saying...


Steve

[stevebrot]

Back when I still owned my M series 28mm/2.8 I compared it against a friend's bayonet Takumar 28mm/2.8, and we were both astonished to find that we preferred the Tak's rendering by far.

That is an interesting comparison. The M 28/2.8 was price-competitive new against lenses from Vivitar (similar value now as well)* and I have often wondered if there was much difference between it and the Takumar Bayonet (aka Cosmicar and CPC Phase 2) 28/2.8. The K-Mount Page uses the same optical diagram for all four variants.


Steve

* The M 28/3.5 was the higher performance version. FWIW, most name-brand 28mm lenses of the time were quite competent with the biggest difference between offerings being distortion and flatness of field. In 1982, I paid extra (~$50 more IIRC) for a Tamron 28/2.5 over the Pentax-M 28/2.8 based on published test results at the time.

[Dartmoor Dave]

That is an interesting comparison. The M 28/2.8 was price-competitive new against lenses from Vivitar (similar value now as well)* and I have often wondered if there was much difference between it and the Takumar Bayonet (aka Cosmicar and CPC Phase 2) 28/2.8. The K-Mount Page uses the same optical diagram for all four variants.


Steve

* The M 28/3.5 was the higher performance version. FWIW, most name-brand 28mm lenses of the time were quite competent with the biggest difference between offerings being distortion and flatness of field. In 1982, I paid extra (~$50 more IIRC) for a Tamron 28/2.5 over the Pentax-M 28/2.8 based on published test results at the time.

Thanks Steve. That's helpful info, and it tallies with the fact that my friend and I couldn't see any difference in sharpness at any aperture on his Spyder calibrated iMac. It came down to us both preferring the more naturalistic colours and contrast from the bayonet Takumar. And I agree about the 28mm/3.5 being in a different league altogether. I'm pretty sure it's optically the same as the M42 Takumar 28mm/3.5 that I still own and love.

[GUB]

GUB did a test and shows it outperforms the M/K/Takumar lenses. It could probably only match the A series since it's the same design.

More to the point my copy outperforms the examples of the other 135s I have. I think sample variation might explain other peoples experience with the Tak Bayonet.
The poor old much maligned Takumar Bayonet group. - PentaxForums.com
But having said that when i got my first Tak bayonet 28 2.8 it immediately replaced my M28 3.5 due to IQ.
But about coatings - they were originally about increasing the T stop of a lens in the days that Iso 200 was a fast emulsion. They incidentally boosted contrast and their introduction finally made zooms less than horrible. I note the tone of this thread automatically presumes no or less coating is bad - coating = good. As far as old primes are concerned I find the level of coating almost irrelevant and actually tend to prefer those less coated ones.

[stevebrot]

But about coatings - they were originally about increasing the T stop of a lens in the days that Iso 200 was a fast emulsion.

Interesting! That makes sense, though I suspect that flare reduction for periscopes, binoculars, and bomb-sights was the rational behind the Germans classifying the 1935 Zeiss coating technology as a closely guarded military secret; such was a bargaining point at Yalta when the Zeiss works were granted to the Soviets as war reparations. My memory at the time that multi-coating first debuted was that flare reduction (widely declared as "flare free") was the marketing point for Pentax SMC lenses.


Steve

(...interesting discussion in the Wikipedia article...https://en.wikipedia.org/wiki/Anti-reflective_coating...)

[GUB]

Interesting! That makes sense, though I suspect that flare reduction for periscopes, binoculars, and bomb-sights was the rational behind the Germans classifying the 1935 Zeiss coating technology as a closely guarded military secret; such was a bargaining point at Yalta when the Zeiss works were granted to the Soviets as war reparations. My memory at the time that multi-coating first debuted was that flare reduction (widely declared as "flare free") was the marketing point for Pentax SMC lenses.


Steve

(...interesting discussion in the Wikipedia article...Anti-reflective coating - Wikipedia...)

Ummmm errrr I am only parroting what I read on here somewhere and it made sense to me too. But I can't source my statement and your bigger world view makes sense also. It was the flare reduction that made zooms viable (barely) for sure. I am starting another thread showing Pentax 28mm shots comparing coatings on the older glass.

[stevebrot]

Ummmm errrr I am only parroting what I read on here somewhere and it made sense to me too.

The section of the Wikipedia article on index-matched coatings mentions that increased transmittance was how the phenomenon was originally detected, so all is not lost.

Anti-reflective coating | Index-Matching - Wikipedia


Steve

[UncleVanya]

I can't find it but there was an extensive review of Pentax 135s that ranked the takumar bayonet 135 f2.8 was number 1 or 2 and was above the K 135 2.5.

[SunnyG.]

Interesting idea... Wondering though, can a small company make decent coatings?

Well some, if not all are good! Some of them are successful.

---------- Post added 12-02-18 at 06:12 PM ----------

easy: buy one and send it in for the coating process, get it back, shoot, and report back...

Well if I lived in the US, I would've done. But the cost of shipping would burn a hole in my pocket

---------- Post added 12-02-18 at 06:14 PM ----------

They are coated, what made you think they weren't?

I was referring to SMC. They don't have SMC coating.

---------- Post added 12-02-18 at 06:16 PM ----------

I have a Tamron 300mm f/5.6 in M42 mount that has lost bits of its coating on the front element. It was only $10 and the cost of restoring it would probably exceed its value. Interesting to know it can be done, though.

Of course it can be done. Just search on Google. Maybe with modern it might exceed the value you bought it for.

---------- Post added 12-02-18 at 06:20 PM ----------

I would be seriously surprised if that is the cost. Each element has to be polished to remove the existing coatings and then recoated.

Some of the services I found only work on film lenses. This to me indicates $$$$

Well you could opt for Recoating without polishing. In theory. I don't know for sure. I think if someone emailed and asked. That would be helpful.

---------- Post added 12-02-18 at 06:25 PM ----------

Who are these re-coaters you found on google? Please share you findings so we can help you evaluate. Guessing that only the best lenses for film, video, and stills would be worthwhile, but who knows?

Dulcos is the only one I remember. Well you're right about that one. it's not for cheap budget lenses. But one could do this as an experiment.

---------- Post added 12-02-18 at 06:28 PM ----------

The Takumar bayonet series lenses were budget models.

SMC Pentax lenses multicoating is excellent even by today's standards.

Why not simply trade up? It would probably be less costly.

Chris

I was thinking, more on the lines of an experiment. Similarly, how some people give old cars modern touch, when they hot rod them. Think of this as a form of "lens hot rodding". Not for everyone.