Just a quick update on my front focus situation. I wanted to get a baseline of all the lenses I use before calibrating. In summary...all of my MF lenses (Oly, MD, Kiron, Rokinon) all front focus about the same. Now all my Canon EF AF lenses seem to be spot on or just slightly front focusing.
My 5DMK2 had two shims, a thick and thin in relative terms...they're pretty thin. So I decided to take the thinnest shim out first. Results of this were slight back focus. To prove my sanity I decide to leave the thin in and take out the thickest. Results were major back focus.
So with both shims I was getting moderate front focus. With just the thickest shim I was getting slight back focus. The ticket for me was placing very slim strips of masking tape (cut with a razor blade) on each side of the thick shim. Now I'm 98% spot on.
I think the take-away for this is that everyone should test their MF lenses and MUST calibrate if they are off. Now for more testing and playing.
-Roy