Quote Originally Posted by Robert
Quote Originally Posted by Ed Sukach

Hmm... Wondering about this. Do you have any references re: f/stops and resolution?
Diffraction limits?
also this from the Large format lens testing page.
Scroll down to the discussion near the bottom.
Both web siites are excellent. Thanks for posting them.

I think that it should be noted that, in theory, the *least* diffraction will occur at the largest possible aperture; but it should be noted that that is only one factor affecting the performance of an an optical system.

Be *very* careful about defintitions here - do not confuse "diffraction limits" with something limiting the entire lens performance - "`Diffraction limited at...' indicates that aperture where lens performance will not *improve* by additional `stopping down'". The lens performance could be extremely high to start with ... so any "improvement" would be very difficult to achieve.

The web sites are in FAQ format - and a diligent study of the questions and answers will provide a good education in just what happens when we talk about the phenomenon we call diffraction.

Lens resolution is not *only* affected by diffraction - there are many, many other optical characteristics involved.