Both web siites are excellent. Thanks for posting them.Originally Posted by Robert
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.