I included "very general" in the title, because I am not worried about numbers here. I have two lenses, a Komura Commercial 210 f/6.3 and Nikkor-S 135 f.5.6, which stop down to 45 and 64, respectively. Since my principal interest is B&W portraiture and I shoot only HP5 and print only to 11x14, both of these lenses is more than adequate for this purpose. I already know this and am perfectly happy with both lenses.
I am posting this in case someone sees something I am leaving out in my considerations, below.
I do shoot other subjects, and recently was shooting some flower and leaf still life scenes in the garden fairly close up, requiring small apertures even after movements. It piqued my curiosity about the lenses' performance at these f/32-and-smaller apertures, where I am aware that diffraction limitation enters in. Thus, just for curiosity's sake, I wish to run a simple comparison.
My idea is tape some black nylon screen material tightly against the back wall of our fairly smooth, light-colored stucco house and make images at f/16 (which is probably near optimum sharpness for these lenses) /32, and /45 (plus /64 with the 135) from 5-6 feet away.
I know that various lenses are optimized for smaller or greater distances; again, this is very general, and unless one of the lenses really starts losing sharpness at 2-3 feet that could affect such close-ups as I mentioned, which I find highly unlikely, this test, with screening pretty much filling the frame, should offer reasonable comparison of sharpness at the apertures selected.
I know that the enlarger must also be aligned, that it, too, has a lens, and that the photographic process has more variables than a barrel of monkeys. Again, I'm not going for numbers, just planning to poke around, so to speak, to see if the limitation will show up at all, and if so, how much, within my general parameters.
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