A stupid question: sharpness/resolution vs focus

Started Nov 27, 2005 | Discussions thread
beerguy Senior Member • Posts: 2,539
Re: A second stupid question

karl vollmers wrote:

So given that diffraction is a problem with small apertures. How
did the A. Adams and others in the f-64 crowd do it or deal with it?

I'm not sure how often they actually shot at f/64. The f/64 Group was dedicated to images that were sharp from edge to edge. A lot of that can be accomplished with camera movements (law of converging planes), which allows you to stop down a bit less. OTOH, the lenses they used back then were probably not as razor sharp as today's glass, and diffraction was less noticeable. Or they were willing to take the hit from diffraction to get maximum DOF. On a 8x10 contact print, it may not even be noticeable.

I looked at my collection of LF glass, and most stop down to f/64. One, my Nikkor 450M, stops down to f/128. However, it starts at f/9. I can't recall ever having stopped down past f/32, and f/22 is more typical. (Most LF lenses specify the image circle at f/22, so if you are using extreme camera movements, you need to stop down to at least f/22 to prevent vignetting.)

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