Juergen Sattleru , Oct 11, 2009; 09:28 a.m.
What settings did you use? DId you read the manual? The AF on this camera is VERY different from any previous non 1Dx camera. I use this camera for wildlife photography and use AI Servo with single point AF with expansion and slow AF tracking. My 40D can not hold a candle to the 7Ds AF capabilities - it tracks so well, that almost all my shots are now perfectly focused, even for birds in flight.
There are a numbe of articles on Canon's website to help you chose the right settings.