Ouch! If you've been playing with the lens mount you might want to do some focus testing (e.g. on a sheet of newsprint) to check that the camera still focusses correctly across the entire frame at wide apertures.
I had my own scare recently, but it turned out worse. Early in September I was in WA and had climbed out of bed and driven out to Bluff Knoll (in the Stirling Range) for some dawn shooting. It was cold, I was tired, and it didn't turn out well. Beside the car, I put my 17-40mm lens on my 30D, attached it to the top of my tripod, turned back to the car, and heard a very nasty "crunch" as the lens/camera hit the asphalt! Turns out I didn't pay attention, and only balanced the camera on the tripod rather than attaching it!
The lens hood was cracked in two, the filter on the lens was bent and wasn't going to detach, the lens' focus ring wouldn't move, and in fact the lens rattled! Not a good start to a week's shooting in a remote location!
OK, I got over my initial shock and switched to my 28-135mm lens. But the 30D simply reported "CF Err" and refused to do anything useful.
OK, switch to the backup 350D body and get shooting: the sun was about to come up!
In the end I did get some nice images that morning...
Back at camp later I was able to disassemble the 30D and check the internal connections (I
modify the internals of these cameras for a living, and I had a reasonable toolkit in my bag). Luckily that fixed the problem, and in fact the camera has been working flawlessly ever since. It does have a few battlescars though. I like to think the RRS L-plate on the camera did at least something to protect it as it bounced on the bitumen...
As for the 17-40mm/4 L lens, the repair bill is over $700. But at least I only have to pay a $250 excess to my insurance company, and I've got a loaner 16-35mm/2.8 while Canon wait for parts from Japan.
