I have had this lens for about a month and have been enjoying it. However, tonight I noticed when I went outside to take some shots that it didn't seem to be locking focus on the left hand side. Even if I placed an objected toward the left side of where I was aiming, making sure that the object was closer to the lens than anything on the right side of the view finder, it still seemed reluctant to grab focus toward the left.
I put my 5D3 in a different focusing mode, eight-point selection to the far left, and it managed to lock on okay then. However, once in awhile the camera would seem to do a "freeze lock" and even if I took my finger off the shutter, I could immediately press down again and take a picture without the lens regaining focus.
I tried to replicate this issue on my 5D2, but I can't seem to reproduce it. Everything seems to work normally.
When compared to my 24-105L on my 5D3, aiming directly at the edge of a table, the 24-105 picks up the table in a completely perfect focused line in the view finder. The Tokina 16-28 only picks up the right side of the edge of the table. Again, this doesn't seem to be an issue with the 5D2; the lens worked fine.
I have used FoCal to calibrate the lens on both the 5D2 and 5D3. My adjustments with the 5D3 were -11 for the wide end, and +3 for the telephoto end.
Do you guys think this is a calibration issue, or do you think I should return this copy of the lens and see if I can get another?