I am seeking advice concerning issues I have been experiencing with my 7D and the auto-focusing system. I have had the camera for a little more than a year (has been fantastic) but recently for some unknown reason the majority of pictures I took were out of focus. About three weeks ago I sent the camera and one of the lenses (24-70 2.8f) to Canon in Irvine, CA. for repairs. The repair center sent my equipment back which cost me a couple hundred to fix the camera (out of warranty). The repair center also performed some major repairs to the lens (changed the motor, etc.) which thank goodness was still under warranty. When I received it back from Canon the focusing issue appeared to be worse than it was when it was originally sent in for repairs.
I am not a poster on this forum but do visit frequently as it provides great information. I reviewed several threads and came to the conclusion that I needed to try testing my lenses on another camera and also attempt to microfocus/calibrate these lenses with my 7D before I contacted Canon about the issues I was still experiencing. A co-worker has a brand new 60D which I used to test two of my lenses. The testing was performed with a tripod, IS off, handheld remote to activate the shutter, bla…bla…bla. Bottom line was the 24-70 and the 70-200 (2.8f IS II USM) were both tack sharp using his 60D. It was obvious that neither lens has focusing issues.
The next thing I did was to take my 7D with the same two lenses and performed similar tests to the ones I performed with the 60D (using tripod, etc.). After I performed the standard tests (majority of the shots were blurry) I also tried using “live view”, turned off the autofocus on each lens (along with IS) and proceeded to focus manually. The photos for both lenses in live view were slightly blurry at 4.5f with a shutter speed of 1/1250 but when I turned off the live view and used the 7D’s autofocus system the pictures at the same settings were definitely a lot more blurry.
I found a thread on this site that helped me with microfocusing the 7D so I followed this procedure with both lenses. When I finished the calibration, the focusing issues with the camera were substantially better but not fully corrected. It seemed that both lenses from 4.0f and smaller apertures would produce pictures that were sharp and in-focus almost 100% of the time. From 3.5f to 2.8f the pictures begin to degrade and by the time I use the 2.8f setting only about half of what I shot was in focus. The one thing that bothered me about the microfocusing outside of not completely cleaning up the focusing issue was with the final adjustment numbers. It appears the 24-70 is really out of whack compared to the numbers that were stated of what was to be expected in that microfocus thread on this forum. The 70-200 ended up at +2 (very reasonable) but the 24-70 ended up at -18.
So based on this information, here are my questions that hopefully one of you can help me with:
1. Should I expect a little blurriness which I am experiencing at 2.8f with this camera and lenses or should it be just as sharp at 2.8f as I am seeing at 4.0f?
2. Should the microfocusing on the 24-70 be that far off (-18) or do you think there is still something still wrong with the autofocus in the camera?
3. Why would I be able to get a sharper image with manually focusing the camera myself using live view over the autofocus system unless there is something still wrong with the autofocusing system in the camera?
My expectation with the money I paid for this camera and “L” lenses is that my photos should be tack sharp down to 2.8f. Can someone please tell me if my expectations are too high? One last thing is that I also have a 100-400 4.5f – 5.6f and calibrated it too. I didn’t spend nearly as much time with this lens as the two others but the microfocusing adjustment ended up at -7. Any help would be much appreciated.
Thanks - Mike