I would really like for someone out there in the ULF world to respond to my question: Why do some process lenses like the APO Nikkors commonly used by ULFers, stop down to, say,
f 128? I know generally about the phenomenom of diffraction - and apertures as small as 128 would seem to introduce objectionable diffraction. Why then do some of the graphic arts lenses seen commonly today in the used market stop down so far?
I can hazard only one guess:
Is diffraction not an issue at, say, f 128, if what you are photographing is line copy onto huge sheets of litho film.
Many thanks,
Robert McClure
Atlanta
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