I have thought that my L lens seems to suffer from some sort of front/back focus problem, and believe my theory may be correct.
I have attempted to test the focus by running a MFA test, though am not sure if I have done so correctly and hoped to post my test results here in case any of you kind people may have other recommendations, advice or tips.
I shot at 400mm, using f/6.3, iso of 500 and for all but the last (+10) image, 1/400 shutter speed.
The object was approximately 11m away from the camera (not quite the 50x focal length rule), and the area of focus was the barcode.
(no adjustment '0'):
Hopefully you will share my opinion that the first (no adjustment) and last (+10) are the worst of the examples presented.
From the examples given, I seem to lean to (+5) giving the best clarity of the barcode and text, though believe it is or it could be anywhere from (+2) to (+7)?
I appreciate with the noise and image distance it is perhaps not a great test, but would greatly appreciate any help and advice all the same.
EDIT: Added links to images as they do not appear to be embedded?
[Edited 2013-03-20 05:13:04]
[Edited 2013-03-20 05:20:52]