Urgent: Which is better 40D or 5D autofocus for moving subjects?

I have to make a decision today in order to get the body tomorrow.

Which has the better AF for moving subjects - (alpine skiers)?

The burst rate is a plus - I know that. I have been shooting this with a 5D for a couple of years because the 5D AF was better than the 20D. I have to shoot a ski meet on wednesday so I need to make the decision today.

I'll be using this with a 300f/4 IS USM, a 70-200 f/4L IS USM and probably a 17-40 for closeups.

J.

I will not comment on experience here, but purely from a SPECIFICATION standpoint, the 40D is superior.

It has NINE cross type sensors that are active at F/5.6 or faster, and the centre point is a diagonal cross active at F/2.8 or faster.

The 5D has one cross type sensor active at F/2.8 or faster.

So all the 40D AF points are crosses and are much more sensitive to light.

Now in practical use, I can't comment. Just stating specs for you.

I would think that the 40D would be the better camera for the application you speak of. But I am not sure I would want to purchase a different camera to be used on such short notice, especially when it comes to learning how a new camera's autofocus system works.

I dont think many (if any) sports guys are using the 5d... if thats a clue..

I had more shots off with a 40d than a 5d, 5d has assist points around the centre point to help.

40D definitely (I shoot with both).

Though my 5D shines in so many ways, Ai servo is not one of them. If focus ok, but is not lightning fast. The 40D has a far superior autofocus system IMHO. Much quicker and follows much better.

i had both and the 40d wins.
Rob.

Neither of your lenses will make use of the extra sensor in the centre focus point of the 40D, though they'll still benefit from the 9 cross point sensors. I have excellent results using the 70-200 f/4 IS with AI Servo on the 40D. Can't speak for the 5D.

40D wins here. AF is better, especially on on-center points.
6.5fps certainly helps as well.

a 1D Mk II or III will suit what you are looking for better

neil_r wrote in post #4849692
a 1D Mk II or III will suit what you are looking for better

And buy a new car while you're at it.

40d is far superior for sports type use and/or focus and tracking abilities. The 5d is better suited for landscape, and/or more still subject....granted, i have been finding that i use my 40d for even these types of applications over my 5d. the Digic III along with 14bit really has a leg up on the 5d.

that being said, when is the 5d replacement coming?

The 40D would get my vote. But it is different than a 5D and I would not want to have to learn a new body that fast.

I missed the deadline for shipping, so the point is moot anyhow. I now have more time to consider the issue.

I'm not worried about learning a camera fast, lots of commonality with the other canon bodies I have.

If the kid's team goes to state, then I'll do it. I'll know on wednesday and then we'll decide. That will also give me time to get my L brackets from RRS too.

J.