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10-04-2009, 10:45 PM   #31
Nubi
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Yeah, but these "parameters" were exactly what they did not pay a whole lot of attention to when developing DA limiteds. They certainly did that with DA* series. At least that is what the article said.

10-05-2009, 05:25 AM   #32
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the set parameters arent exactly as scientific as you might think, nor do they give the most accurate measurement of a lenses ability. or at least it didn't. I have an old Asahi Pentax Takumar Lens Manual (a dealers piece) that talks about lens testing (resolution, response function, etc, etc) and it, at least to me spelled out pretty clearly that there wasn't any widely accepted "good" tests. I wonder how much if any that has changed?

I also very much disagree with the thinking that modern glass and lens element construction is 'that' much better today. I don't believe so. has it improved? yes, but not as much as one might tend to believe. when it comes to the performance of the M vs the DA, I dont believe it can all be chalked up to the DA being modern. for comparison, the 18mm fish-eye-takumar vs the later 17mm fish-eye-takumar. a world of difference in not a lot of time. the modern coatings certainly make differences, but the SMC aspect isn't very conclusive, as that hasn't really changed much in terms of what it offered then and now. the other coatings will make a difference, but seeing the two optical formulas, its clear to me the higher performance is almost exclusively due to this aspect. even small changes in an optical formula can yield a big difference in performance.
10-05-2009, 07:17 AM   #33
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What would be the size of a DA 40mm F2.0.....equal to the DA 70 ?

Kind regards
.lars
10-05-2009, 10:57 AM   #34
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QuoteOriginally posted by séamuis Quote
the set parameters arent exactly as scientific as you might think, nor do they give the most accurate measurement of a lenses ability. or at least it didn't. I have an old Asahi Pentax Takumar Lens Manual (a dealers piece) that talks about lens testing (resolution, response function, etc, etc) and it, at least to me spelled out pretty clearly that there wasn't any widely accepted "good" tests. I wonder how much if any that has changed?

I also very much disagree with the thinking that modern glass and lens element construction is 'that' much better today. I don't believe so. has it improved? yes, but not as much as one might tend to believe. when it comes to the performance of the M vs the DA, I dont believe it can all be chalked up to the DA being modern. for comparison, the 18mm fish-eye-takumar vs the later 17mm fish-eye-takumar. a world of difference in not a lot of time. the modern coatings certainly make differences, but the SMC aspect isn't very conclusive, as that hasn't really changed much in terms of what it offered then and now. the other coatings will make a difference, but seeing the two optical formulas, its clear to me the higher performance is almost exclusively due to this aspect. even small changes in an optical formula can yield a big difference in performance.


I think this is a terribly interesting discussion for me. Obviously you seem to know a whole lot more than I do about optics. But Let me share something that came up in the discussion that I had with one of the guys that works for Nikon in the optics division. My cousin works for Canon's printer division, and his classmate from college works for Nikon. I was recently in Tokyo for vacation, and three of us got to talk about lenses.

Nikon guy thought that the technology is far superior than it used to be, at least within the company that he works for. Because of the popularity of the digital media, the manufactures had to re-think the lens technology since so many users these days crop picture for magnification. More details in the form of improved sharpness was clearly in demand. So what they worked on was to reduce the chromatic aberration as much as possible, and he says this is one aspect of digital camera lenses that are so very different from the film era lenses. He says that the basic concept of optics design has not changed much, except that now computer simulation is available, which cut the R&D time considerably. Also, with many simulations, one thing they discovered was to use the ED glass in a way that wasn't used before(at this point of the discussion, I was just minutes away from complete cluelessness). He said that this was more of case as the FL of the lenses got wider and wider. In the old days, ED glass was very expensive to manufacture. But these days, the cost has come down dramatically. Because of this, within the cost constraint, they can shoot for higher resolution than they used to. He also says that the consistency of the lenses have also greatly improved in the manufacturing process. Also for them, nano crystal coating allowed them to take a leap in terms of reducing flares and so on.


He didn't know too much about recent endeavors of Pentax though. When I told him that I shoot Pentax, he said "ah, the purist."

What do you think?

10-05-2009, 11:17 AM   #35
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QuoteOriginally posted by Nubi Quote
I think this is a terribly interesting discussion for me. Obviously you seem to know a whole lot more than I do about optics. But Let me share something that came up in the discussion that I had with one of the guys that works for Nikon in the optics division. My cousin works for Canon's printer division, and his classmate from college works for Nikon. I was recently in Tokyo for vacation, and three of us got to talk about lenses.

Nikon guy thought that the technology is far superior than it used to be, at least within the company that he works for. Because of the popularity of the digital media, the manufactures had to re-think the lens technology since so many users these days crop picture for magnification. More details in the form of improved sharpness was clearly in demand. So what they worked on was to reduce the chromatic aberration as much as possible, and he says this is one aspect of digital camera lenses that are so very different from the film era lenses. He says that the basic concept of optics design has not changed much, except that now computer simulation is available, which cut the R&D time considerably. Also, with many simulations, one thing they discovered was to use the ED glass in a way that wasn't used before(at this point of the discussion, I was just minutes away from complete cluelessness). He said that this was more of case as the FL of the lenses got wider and wider. In the old days, ED glass was very expensive to manufacture. But these days, the cost has come down dramatically. Because of this, within the cost constraint, they can shoot for higher resolution than they used to. He also says that the consistency of the lenses have also greatly improved in the manufacturing process. Also for them, nano crystal coating allowed them to take a leap in terms of reducing flares and so on.


He didn't know too much about recent endeavors of Pentax though. When I told him that I shoot Pentax, he said "ah, the purist."

What do you think?
not sure what to think. its hard to compare old vs modern lenses when referring to two completely different companies. im no optics expert by any means, but from what you have posted, I wonder where Asahi Optical stood in terms of lens design in the 50s, 60s and 70's. reducing chromatic aberration was a big deal, even back then. particularly in the 60s. Asahi Optical really put a lot of effort into this. my Takumar lens manual goes into this in great detail (I should scan some of the pages) at least for Pentax, I don't think it was that different back then compared to today. I believe quality control is certainly better today in regards to glass construction, but Asahi Optical at no small expense, tested every single Takumar lens that left the factory, and the engineering behind the manufacture of glass has not changed so much as to consider it *that* much better today. at least I don't believe it to be the case. as for ED glass (as well as Aspherical) I dont know what to say really, I read an article on a blog not to long ago (dont remember the link) referring to canon lenses and how they actually used to use ED glass in a more practical and more beneficial manner during the FD days as opposed to the modern lenses... this is apparently directly related to the lower cost nowadays. basically saying that canon uses them more as a marketing gimmick than an actual way to improve a lenses ability, like they did when ED glass was much more expensive. so who knows. I certainly dont.

"the purist" he meant that in a good way?
10-05-2009, 12:02 PM   #36
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One of these days when I have a little time, I need to get my integrating sphere at and shoot light through the lenses and come up with a transmission evaluation for the Taks, K, M, A etc lenses.
10-08-2009, 02:41 AM   #37
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QuoteOriginally posted by Recercare Quote
What would be the size of a DA 40mm F2.0.....equal to the DA 70 ?

Kind regards
.lars
The M40/2.8 is 63x18mm at 110g and the DA40/2.8ltd is 63x15mm at 90g.

Konica made a Hexanon AR 40mm f1.8 pancake at 58x27mm and 140g, probably the sharpest 40mm pancake anyone made (http://www.buhla.de/Foto/Konica/Objektive/e40_18.html), but I like the Pentax 40mm also. The DA70ltd is 63x26mm at 130g, so your guess is very good.

I think that Pentax took the M40 designed and tweaked it a bit t improve it within the APS-C frame, and doing this they sucrificed quality outside the APS-C frame, so while it work on FF, it's corners are not as good as the M40. In the process they also got a slightly shorter minima focus distance.
10-08-2009, 06:08 PM   #38
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Look what I bought today!!!!



Pentax Fish-Eye Takumar 17mm f4 Screw Mt w/ K Adapter - eBay (item 380164719931 end time Oct-08-09 16:08:57 PDT)

10-08-2009, 06:28 PM   #39
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ive been wanting to buy that for quite some time. I got "suckered" into the 11/18mm fish-eye-takumar instead. I will have one someday though.
10-08-2009, 06:55 PM   #40
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QuoteOriginally posted by Douglas_of_Sweden Quote
The M40/2.8 is 63x18mm at 110g and the DA40/2.8ltd is 63x15mm at 90g.

Konica made a Hexanon AR 40mm f1.8 pancake at 58x27mm and 140g, probably the sharpest 40mm pancake anyone made (http://www.buhla.de/Foto/Konica/Objektive/e40_18.html), but I like the Pentax 40mm also. The DA70ltd is 63x26mm at 130g, so your guess is very good.

I think that Pentax took the M40 designed and tweaked it a bit t improve it within the APS-C frame, and doing this they sucrificed quality outside the APS-C frame, so while it work on FF, it's corners are not as good as the M40. In the process they also got a slightly shorter minima focus distance.

Voigtlander Ultron 40mm f/2.0 is dia.63mm x L24.5mm x W200g. It also covers a 135 film frame.
10-11-2009, 08:42 PM   #41
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QuoteOriginally posted by dave9t5 Quote
Voigtlander Ultron 40mm f/2.0 is dia.63mm x L24.5mm x W200g. It also covers a 135 film frame.
It is a completely different design than the Pentax M and DA 40mm though. There was also a Chinon 45mm pancake.
10-11-2009, 09:58 PM   #42
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I wish they did make it 38mm, I would of liked the extra FOV!
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