Upload & Sell: Off
First a little of my background: I shoot sports (90% of the time). I use AI Servo with the center point 90% of the time (the rest I'm using a different point or one shot focus). I'm generally shooting at ISO 1600 at shutter speeds of 1/400 at the low end and 1/800 on the high end. I use back-button (*) focus all the time, no matter what focus mode I'm using.
The camera I use, the Canon 30D was sent in for the Error 99 fix in late August/September 2009 and seemed to work great for me until about September 2010, when I noticed that a few shots were back focused (not enough to miss critical shots with no replacement). I didn't shoot a ton of sports last school year, but I this school year and noticed that more and more of my shots seem to be back-focused.
I primary have used the Canon 70-200mm 2.8 (non IS) since September 2010. I have used at least four versions of this lens at various times and with each, I seemed to be getting back-focused action photos. The lens I'm using right now is a friends and when it's on, it's the sharpest lens I've ever used for a 70-200 2.8.
The following set of images are from a hockey game last night. This is shot through the glass at ISO 1600, f2.8 and 1/640th. Through the glass, which only exacerbates the problem.
It took five shots to get a sharp face (not shown in the last photo).
I could post countless samples of recent games where it seem the next person back is in focus, not the person I'm focusing on.
Any ideas? Would this fix be covered by Canon? I can't afford to have it sent in if costs $200.
PS: I have noticed any back focus issue when shooting in One Shot focus with stationary targets.
PPS: I test this same lens with a Canon 7D and saw no issue that's couldn't be explained by user error.
PPPS: I have noticed this issue with the 16-35mm f/2.8 II as well.