Originally Posted by
Nathan Potter
I use this lens a fair bit and agree with Oren. The optimal aperture really depends on the subject matter you wish to capture. And by optimal I suppose you mean resolution.
In use, I typically focus only at the center since it gets progressively difficult to see an image toward the edge of the frame (in fact impossible at the edge). Many people use this lens in a fixed focus arrangement in schemes that approach a pinhole setup.
I use a hyperfocal chart which tells me the distance to focus on for obtaining a DOF from near point to infinity. I see from my data sheets that I most frequently use f/22 where for a COC of 40 µm (12.5 lp/mm) I get a DOF from 4 ft. to ∞. For that setting the hyperfocal distance is 8 ft. - which I simply estimate. Even at f/22 I don't think you'll see 12 lp/mm near the edge of the frame with 4X5 format owing to a high degree of elongation distortion mixed with other aberration distortions.
Nate Potter
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