Important Update on the 1D3 AF Issue
October 18th, 2007: You might have heard that the 1D Mark III has some performance issues when it comes to autofocusing on bright, sunny days. Well, it seems that Canon has finally identified the source of the problem, and it has something to do with the submirror assembly. In other words, cameras have to be recalled and the relevant components replaced. Please read this forum post for more details on the fix for the 1D3 AF problem.
Miscellaneous Tips
How to test your 1D Mark III’s AF (auto focus)
Prophotohome.com has an excellent set of written instructions (even comes with a video clip) on how to ensure that your camera’s AF mechanism is working properly.
Limit continuous shot count
When the Mark 3 is put into high-speed, 10 fps (frames per second) mode, it’s not possible to get only 1 shot, says David Probst. At best, you can fire as low as 2 or 3 shots if you’re really conscious about letting go of the shutter as soon as a shot is fired.
From page 172 of the Canon EOS 1D Mark III instruction manual you can limit the number of shots taken in high speed in continuous mode, from 2 to 99. So, if you only want to shoot 3 frames per 10 fps burst, just set it accordingly under Custom Function III — 17. A screenshot of the relevant portion of the user guide is shown below: