auto focus speed

[Raaf Hornet]

Hi all, im looking to replace my Canon 50E film camera with a 50D or if I can reach it a 7D. My question is, is the auto focus speed in the body or in the lens. I like to take pics of military jets and will be getting a canon 100- 400 USM lens. Will there be any focusing speed difference in the 50 compared to the 7D ? Hope this makes sense. Thanks for any info, Jeff

[ricktas]

both! Certainly the camera body plays a part, but so do the mechanics inside the lens. So there is no definitive answer, it really depends on the actual camera and lens combination being used at the time.

[Steve Axford]

Mostly the lens. The 100-400 isn't a very fast lens.

[MarkChap]

In good light I doubt you would notice a difference in speed between the 2.

Certainly the 7D will track better than the 50D