I've been testing some of my large format lenses in the past few days. I've noticed that none of them are as sharp (in the center) at f32 as they are at f16.
-This is across many different focal lengths and many different designs.
i know that this is caused by diffraction at small apertures.

But really, ive never had a good explanation of why this occurs, and why it only appears at small apertures.
Could someone answer this? THX