20D vs 5D autofocus

[Andrew Teakle]

I know the 5D has the 6 "invisible" focus points, but does this increase the AF accuracy (and speed?) compared to the 20D. I'm doing a lot more bird and wildlife photography these days and primarily use the 100-400 IS, but I'm finding the focus to be quite poor when tracking moving subjects. With a teleconverter, forget it! Now I understand that a 1D(and Ds)MkII with an f/2.8 or f/4 lens would work better and I'm busting to get one, but I'm sure my Eos 3 autofocused better than the 20 D with this lens.

I love the 1.6x "extension" of the 20D, and 8MP is normally fine for my needs for this kind of subject. I'm considering the 5D for the rest of my nature and landscape work, and would be curious to know users' experience with it for moving subjects.

I hope this topic hasn't been covered ad nauseum in previous posts.  

Thanks in advance,

Andrew

[Julius]

I have the 5D as well as the 20D but I don't normally shoot birds. In the few times I have shot them, I find the 5pfs of the 20D to be adequate and the 3pfs of the 5D to be way too slow. The FF of the 5D makes it a good landscape camera. But for serious bird photography you really need the 1D MkIIn. Its high speed continuous mode at 8fps shoots like a machine gun. You need that kind of speed and its 45 point autofocus to catch fast actions. Plus it also gives you the 1.3x cropping factor.

Landscape photography is really the opposite of bird photography. The larger the sensor the better it is and speed is of no consequence. That's why medium or large format is the best. You cannot expect a camera that does well for two such extreme types of photography  .

[jani]

What Julius said.

But yes, the 5D does track better than the 20D, in my experience.

In Tibet, my friend and I shot flying ravens in the afternoon (around sunset, but there was still sunlight). If I recall correctly, I used the 70-200 f/2.8 IS, and my friend the 100-400 IS. I got one or two usable, in-focus pictures, he got at least five, and I think I took several more.

It's possible that my technique was at fault, but I also got better focus tracking with the 5D when I tried it for myself.