Does fluorescent lighting cause back focus?
Tonight I was shooting a meeting in a room that used fluorescent lighting for the first time. My other meeting shooting has been in incandescent lighting rooms. All my shots are back focused by about 6 inches or so.
5D, 100 f2, aperture used was about 2.5, subject distance about 20 feet. And this same camera/lens combo is sharp wide open so it's not an aperture issue.