#5. "I don't think it's your tripod Bob...." In response to In response to 4 Tue 29-Jan-13 09:29 PM by Jim Pearce
I shoot with my 500 f4 AF-S & TC-14E on a 3 series all of the time. You should have about .5" of DOF front and back with that setup - 1" total. I'd try autofocus fine tuning to see if you can get it sharp. You might start with a ruler at 45 degrees to get a better idea as to whether you're back focusing or front focusing.