Originally Posted by
Pere Casals
Bob, the problem if that we won't see in what extent we damage ultimate IQ in the focus plane when stopping for DOF. Say we stop f/32, diffraction limit is 50cycles/mm but it also damages contrast at 25 cycles/mm. We won't see this in the GG, because GG graininess won't allow it.
Also if we have to inspect the GG at f/32 then we have a very dim image.
Also we may not be able to judge how sharp is the “apparently” sharp area, also because film records more than the GG allows to see.
A way to learn it without wasting film is attaching a DSLR (without lens) in the camera back, (I did it by fixing a macro extension ring in a Sinar lens board, and placing the resulting Nikon F mount in the Norma back.) A DX consumer DSLR sports 250 pix/mm which is good to explore DOF vs focus plane IQ.
That way does not substitute tables, apps and calcultions, but's a first hand direct view of the real effects.
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