Summary: I have been a loyal Canon user for many years. I own a 30D and the MarkIIID. The Mark IIID was sent back for the recall to address the AF. The work they did to it negatively effected the color balance. It was sent back to the factory. The factory then lost my camera (having shipped it with the wrong FEDEX number). They sent another Mark III. It had back focus problems. In the meantime, another camera was sent as a loaner.
Do NOT buy this Camera until the AF issue is resolved
Kenny A. Chaffin "Seeking Beginner's Mind", Amazon
6 September 2007
Summary: I've owned this camera for about 3 months and it has been to the factory twice and still will not reliably focus correctly. When it does focus correctly or if I shoot landscapes in manual focus mode the images are incredible, but the AF totally sucks and is completely unreliable. It can't be trusted. I've shot hundreds of comparison shots between the 1D MkIII and my 20D and the 20D outperforms it in AF 90% of the time.
Summary: This new model is so good in many ways, yet is unaccepteble in its current form. It has become well known for its terrible focus issues that Canon has yet to be able to fix. Two firmware updates have been issued as a bandaid, but these have not yet fixed the problem. I recommend you hold-off and wait for Canon to officially admit to the problem and name a fix. Yes, this focus problem is that bad. Expect to have 30-50% of your shots out of focus.
Summary: Most professional photographers have been putting this camera through its paces since its release. MAJOR FOUCUS ISSUES ... AI Servo can't track a static object let alone a moving one. see [...] to review finds. This camera has the potential to be great, but leaves us hollow and wanting.