Arrgh. I just checked my focus again this morning after changing nothing and it is off again. I thought I had this problem licked The only things I haven't yet tried (and I think I need the service manual to do them) are:

  1. Adjusting the mirror
  2. Swapping lens shims
  3. Adjusting the 3 factory trimmed vertical posts in the body that press against the underside of the viewing screen.

The discrepancy distance is about 0.6mm horizontal movement of the focus rail. Read my prior post to see what I have tried.

Can anybody give me any other suggestions to try ?