Well last Friday my 40D and 500mm took a tumble on the tripod. Luckily the legs weren´t fully extended so the drop wasn´t that far. Still though it was far enough to wreck the frame of the 40D. It was a brave thing it did and took the brunt of the fall. The lens didn´t seem to be damaged but the other day when on my 400D it wouldn´t focus to infinity. OH GOD!! I had a few sleepless nights thinking I´d have to fork out 838 euros for a service in Madrid. Yesterday then, driving about in my recently re-engined VW camper, I noticed my 100-400 do the same, it was hunting at infinity. Now, that´s good news. I changed it from AI Servo to AI Focus and guess what? NO ISSUES with either lens. Now I can´t wait for my new 7D and make sure all is well.
What a relief even if my 40D is brown bread…