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02-10-2011, 07:25 PM   #31
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QuoteOriginally posted by selar Quote
The chart is not from Bozhidar Dimitrov, its from Jim Colwell.

Jim Colwell states on Page 3 that his lens rating system is based on his interpretation of the following sources:

- Stan Halpin's collated comments (Concentric Dial-Up Internet)
- Robert Monaghan's 3rd party 'cult classic' and other info (medfmt.8k.com/third/cult.html)
- Lars Kjellberg's Photodo optical resolution 'MTF' tests (Photodo - Photographic lens specifications, guides, discussion and reviews)
- Yoshihiko Takinami PDML optical resolution tests (Yoshihiko's PHOTO site)
- Alex Nemerovsky's collated comments (home.att.net/~alnem/html/pentax_primes.html)
- Frederick Wasti PDML optical resolution tests

"Sharpness is a bourgeois concept." - Henri Cartier-Bresson

but none of the resolution tests prove that the apparent lowering of performance optically is due to miniaturization. where is the evidence to back up your original statement? the overalll size of the lens itself has no bearing on its optical performance. the only thing that has bearing in this regard is the optical design and the quality of manufacture. neither of these things can be in any link you have given proven to be directly related to making the lens itself physically smaller in overall size versus the pervious generation of lenses, in fact it cant be directly linked in any way to designing the lens housing to be smaller, as far as I can see. had you simply said that the M series wasn’t designed optically or mass manufactured to the same high level as Takumars or the K series, you might have some ground here, but to say lower performance is due to making the lens smaller simply makes no sense, and you have yet to provide any evidence to back that statement up. now, since a number of M series lenses were new optical designs versus the K series, its even more difficult to link your ideas to lower quality in performance, because you are comparing different optical designs, not different designs in the size of the lens housing. and since you seem to be focusing on optical performance in all your linked information, the size of the lens itself and general build quality and materials used makes absolutely no difference to the tests. so you are not really sticking to one idea of: "was acheived for less quality than the equivalent K or Takumar (M42) lens."

02-10-2011, 07:29 PM   #32
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nice quote Seamius

i keep meaning to change it but it is relevant to so many discussions here
02-10-2011, 07:32 PM   #33
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QuoteOriginally posted by eddie1960 Quote
and looking through this comparison has several instances where optically identical lenses are rated differently ( ie m35 f2.0 and a 35f2.0)
How do you say they are optically identical, the K35/2 has 8 elements in 7groups whilst the M35/2 has 7 elements in 7 groups (side effect of miniaturization?)
02-10-2011, 07:40 PM   #34
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QuoteOriginally posted by selar Quote
How do you say they are optically identical, the K35/2 has 8 elements in 7groups whilst the M35/2 has 7 elements in 7 groups (side effect of miniaturization?)
no, because the change in optical formula could be easily achieved in either lens housing. there are so many variables to why the formula was changed, that to say its due to miniaturization is a bit of a stretch and seemingly very unlikely. possible, yes but unlikely. also, the miniaturization itself wouldn’t address the difference in performance as a whole, because miniaturization (in this case as you see it removing an element to make it smaller and lighter) may or may not always give an end result of lower performance.

02-10-2011, 07:43 PM   #35
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QuoteOriginally posted by selar Quote
How do you say they are optically identical, the K35/2 has 8 elements in 7groups whilst the M35/2 has 7 elements in 7 groups (side effect of miniaturization?)
did I say the K? buy some glasses mate i said the M and A yet they were rated differently, crap like this invalidates the ratings, it's down to sample variance.
02-10-2011, 07:45 PM   #36
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More examples of how the miniaturization affected the lens design (adversely?):

K 20/4 12 elements in 10 groups
M 20/4 8 elements in 8 groups

K28/3.5 8 elemnts in 7 groups
M28/3.5 6 elemnts in 6 groups
02-10-2011, 07:51 PM   #37
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QuoteOriginally posted by eddie1960 Quote
did I say the K? buy some glasses mate
No, you simply said 35f2, the K series is traditionally written without the K, so one assumes that you are referring to the K series when you write so.

The glasses remark is a personal attack, its none of your business whether I need glasses or not.
02-10-2011, 07:56 PM   #38
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QuoteOriginally posted by selar Quote
No, you simply said 35f2, the K series is traditionally written without the K, so one assumes that you are referring to the K series when you write so.

The glasses remark is a personal attack, its none of your business whether I need glasses or not.
No he didn't. The A and M are/were clearly there. The very idea that you think K lenses function any different than M lenses (because you keep stating it), tells all of us where you are coming from.



02-10-2011, 07:59 PM   #39
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QuoteOriginally posted by selar Quote
More examples of how the miniaturization affected the lens design (adversely?):

K 20/4 12 elements in 10 groups
M 20/4 8 elements in 8 groups

K28/3.5 8 elemnts in 7 groups
M28/3.5 6 elemnts in 6 groups
completely different optical designs you are comparing, none of which prove they were changed for ‘miniaturization’ purposes. also, do the different designs prove that the new designs of the M series are of lower optical quality in general versus the K series in every example of changed optical formula? see mate, you are trying pass something with so little evidence and not taking into consideration all the other factors that it looks like you are trying nothing more than to cover your butt for your original statement which cannot be proved they way you presented it, so its hard to take you seriously at all.
02-10-2011, 08:06 PM   #40
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Why would Pentax take several successful lens design and reduce the elements in them except to make the lens physically smaller?
02-10-2011, 08:12 PM   #41
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QuoteOriginally posted by selar Quote
( ie m35 f2.0 and a 35f2.0)
I reproduce the exact wording, how is clear here that the second 35f2 is an A35/2, simply says "a 35f2.0" for clarity it should have been written as a35F2.0 otherwise one cannot be sure of what series he is referring to.
QuoteOriginally posted by JeffJS Quote
tells all of us where you are coming from.
And where exactly is that? And how does where I come from have any bearing on a lens discussion?
02-10-2011, 08:26 PM   #42
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QuoteOriginally posted by selar Quote
Why would Pentax take several successful lens design and reduce the elements in them except to make the lens physically smaller?
what evidence do you have that they were that successful ultimately? especially compared to later designs? you can make the lens smaller and keep the same optical formula, as ive stated before you have shown no direct evidence that the change in optical formulas was directly related to making the lens smaller. its possible thats the case, but you haven’t shown that. also, you haven’t shown that the change in optical design was directly related to lower performance from the lens itself in all cases.

the K series was a direct carryover in almost all focal lengths from the last generation of SMC takumars, the fact that the Takumars were physical smaller than their newer optically identical K mount brothers proves my point (albeit backwards) that the same optical formulas can be used in a smaller package. Pentax was moving away from these older designs, and as such they redesigned optical formulas for newer lenses, and dropping a number of lenses (such as the venerable and much loved 55mm). now im no fool, and I know full well that Pentax was pushing smaller, they always have been (thats why the larger K series has always stood out as odd) and as years went by quality dropped. (true with all manufacturers, then and very much today) but there is no evidence still, that I have seen that the ‘miniaturization’ is the direct cause for loss of quality or even of changing of optical formulas in all cases. there is also no evidence to show that the change in optical formulas always resulted in poorer performance, which would need be the case to prove you right.
02-10-2011, 08:29 PM   #43
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QuoteOriginally posted by selar Quote
I reproduce the exact wording, how is clear here that the second 35f2 is an A35/2, simply says "a 35f2.0" for clarity it should have been written as a35F2.0 otherwise one cannot be sure of what series he is referring to.
It's completely clear to me. If he'd meant K, he would have said so. You're making assumptions again.

QuoteQuote:

And where exactly is that? And how does where I come from have any bearing on a lens discussion?
That of no experience with any of the lenses you're speaking of and using this 7 year old Pricing chart as a single god-speak tell all reference. Exactly.

02-10-2011, 08:38 PM   #44
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I have shown 3 instances of where the lens elements were reduced, in each case referring the same table, the quality rating dropped.

I am not sure how I can prove conclusively that the lens design was changed to accomodate miniaturization, when I am not privy to internal information at Pentax. The number of lens elements may have been dropped for a number of reasons including flare, cost etc., but at the time the need of the hour was to make the body and lenses smaller to compete with the OM1N, therefore it is the most logical explanation.
02-10-2011, 09:16 PM   #45
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QuoteOriginally posted by selar Quote
I have shown 3 instances of where the lens elements were reduced, in each case referring the same table, the quality rating dropped.

I am not sure how I can prove conclusively that the lens design was changed to accomodate miniaturization, when I am not privy to internal information at Pentax. The number of lens elements may have been dropped for a number of reasons including flare, cost etc., but at the time the need of the hour was to make the body and lenses smaller to compete with the OM1N, therefore it is the most logical explanation.
three isn’t enough, and wouldn’t take into consideration all the variables that come into play testing an old, likely used lens. it certainly wouldn’t address simple sample variation. thank you for proving my point with the above statement. you don’t know, and you cant prove it. and thats exactly what I have been saying, because there is no direct evidence to say thats the cause. thats why I said you shouldn’t be spreading such baseless information, as its not good for the community. they didn’t need change anything to make them smaller, my point about going from the smaller Takumars to the larger K series back down to the M series proves that the size overall can be changed and allow for the optical formula to stay the same. that means that you cant even prove that the changes made were for miniaturization for competing with olympus or anyone else. they already had the knowledge and capability to make the lenses smaller without making any changes optically. im not saying that ultimately they didn’t. maybe they did, but you haven’t proved it. you also haven’t proved that the changes made resulted in lower performance across the board. the biggest way to ‘miniaturize’ would be to simply make the lens slower, and they did that in many cases such as the 85mm going from 1.8/1.9 to f2. this indeed makes a lens smaller and asahi optical did this often well before the M series to have ’standard’ filter ring size across its lens lineup, not really for miniaturization for competition.

so no, it mustn’t be the most logical, at least not from what I see. however, even if it were true in regards to changing optical formulas to make lenses smaller, that doesn’t actually prove or even account for lower performance optically, and since Ihave stated already the overall quality is different that simply testing resolution, your original statement is baseless and should be retracted. i haven’t anything else to say about it all.
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