« on: January 07, 2013, 02:27:10 PM »
I've got the 7D, but to me it was so far off I didn't think the micro-adjustment would work. I also called CPS and the guy wasn't sure if the microdjustment would remember the lens/extender combo as it's own lens, or if it would remember it as the 70-200 II. I'd say 15 feet off at 90 to 100 feet.
AFMA values are stored separately for each lens + TC combo (and with newer cameras, by serial number as well, so you can have more than one of each lens or TC type).
Each unit of AFMA is 1/8 the depth of focus, so with 20 units you can correct for 2.5x the depth of focus - that's a fair bit of latitude in the correction.
Neuro, I just spoke to Phil at Norman Camera and he verified my field test results with the front focusing issue, and also confirmed your info that the 7D with microadjustments for the combo will be treated as it's own separate lens. He's sending me another 2X III, so it must have been beyond what would be considered normal tolerances.