You know, Troy, I am thinking perhaps Chuck has made the most appropriate comment here.
I remember Dom saying to me once that Erwin Puts might not be the most useful source of information, and after reading this paper you put up of his, it is badly written to the point of being obscurist. If I don't mistake, this may be because he is actually trying to argue with Zeiss's claims, by using their own statement from another context against them.
Other than that, he talks like a 19th century schoolteacher, and makes his own points step by step quite unclear. For example, it is not a matter 'Kodak's suggestion' that a 3 to 1 MTF ratio is needed to take the lens out of a film resolution experiment, it is the formula he badly reproduces in the next line which grounds this, by root-sum-square combination of MTF. So a '3:1' ratio gets you a 10% influence - an arbitrary cut.
Further, he double counts the Zeiss 30% contrast rule - first using it, then speaking the formula again as if a 'warning' about even this result. I don't think it's any translation problem -- rather that he wants to use this figure to 'prove' at bottom that someone's lens who is not Leica couldn't possibly have printed the 600lpm figure. Except, of course if you use the 5% original contrast value, they might have.
Now, DSG did raise a question of the completely fictional table Puts pulished at the first, for only diffraction limits - not real lenses. He asked as you and docmass were going through some handwaving, and you put out this paper as some kind of justification. I would like to point out that DSG's question made sense, and he himself said he asked it for lack of a further model to understand why real results as he knew were different than this 'high science' model.
You didn't give him this - you immediately told him his lenses were junk, as a response. And then off to the races, where you begged off knowing 'the physics', and felt it necessary to print to everyone your complaint and your donkey.
Why do I reply, when the whole thing seems pretty silly to me?
Because I find with an inner voice, a kind of instinctive liking for DSG, and the way he asks often according to a genuine sense, and often when the stated logic of a thing seems to be questionable.
Yes, DSG, as I, can stand to be educated on any point. And he is stubborn.
But so are those who really don't know good enough answers to give, it seems often enough.
Better it seems to me to let voices speak, and consider what they have to say. At best, gain a new view of what needs clarifying (as in some recent discussion about D200's, as one example). At minimum, keep our horse-related a$$es in our own backyards, where they belong.
Kind regards,
Clive
Hopefully someone with more technical knowledge of optical physics
than I have.
His point is that lenses are softer WO due to diffraction and get
sharper as you stop down. Just the opposite.
General common optical theory as it relates to diffraction states
that as you stop down more and more from WO diffraction continually
causes a loss of resolution.
Erwin Puts link.....
http://www.imx.nl/photosite/technical/highres.html
Referenced from this post. Read........
http://forums.dpreview.com/forums/read.asp?forum=1027&message=19298923
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