I"ve never had a camera you could do that with I may try and tackle it early on though once I get some time, to read thru the procedure and get enough time to tackle it all at once. . I had a problem with my 85 front focusing at about 20-25 feet shooting 1.8-2.2 or so. closer headshots seemed fine, further way seemed fine, but in that 20 or so feet range from subject, it consistently was focused just enough forward that eyes and such were falling out of focus. So it's something I want to see if I can fix, because otherwise I love that lens.
Thanks for the tip