Autofocus Comparison

[james_alexander]

With the current rebates I think I've finally convinced myself it's time to give up my EOS 3 for a digital body. The

thing I'm most worried about is giving up the autofocus on my EOS 3. How likely am I to be disappointed with the

autofocus on either the 40D or the 5D compared to the EOS 3?

[bkpix]

It depends on how demanding you are. Sports? Birds in flight? You almost certainly won't be as happy. Otherwise you probably won't notice much difference.

 

By the way, keep your EOS 3. It's a great camera.

[alan_myers]

There's no Eye Control on the 5D or 40D, if you used it on your EOS3.... I tried it for a couple months when I first got my EOS3s, but ended up turning it off and never using it again. But, I know a lot of people really love it.

 

AF is reasonably good on the D-SLRs. It's not the 45 points you are used to, which in the EOS3 was the first iteration of the AF system we still see today in all the 1-Series cameras. I tended to use my EOS3s with the Custom Function enabled that AF turned down to 11 or 13 points (I forget which), anyway, so that spot metering could be linked to them. Going to a 9 point AF pattern really wasn't all that different.

 

What is quite different is the crop sensor format. Your longer lenses will really impress, but your wider lenses will disappoint. Of course, a 5D would not have that crop, would be a pretty "seamless" transition.

[david_amberson1]

Coming from an EOS 3, you should probably go with the 5D. But wait, there may be a new 5D coming in a few

months. Its up to you, but you may be angry if you buy a 5D and then the new model comes out 1-2 months later.

The new model will probably have a lot better AF system. The current 5D had a poor AF system compared to current

models. It is still good. Or if $ are big concern, go ahead and get it now because the 5D is pretty cheap these days.

And it still is a hell of a camera even at 3 years old.

 

If you've spent that long on 35mm format, them a crop sensor may bother you. The 40D is an awsome camera(I

owned one), but for those use to full frame, they always seem disappointed with crop IQ. I liked mine though and

now I own a 1D Mark III, the 1.3x sensor images are alot better at than a 1.6 sensor in IQ and same MP count.

Newer full frame is probably mind blowing. Just a thought.

[peza]

I was never really happy with accuracy and consistency of AF with fast lenses on digital bodies. 10D was disaster, 20d was little better, 5D yet a bit better. 1DM3 is great in this respect - in one shot AF, servo is another chapter. Don't use it for stationary subjects. Very accurate and sure footed even with f/8 TC+lens combo (I didn't expect it to be so good).

 

Likely you will be disappointed even with 5D if you have in your bag f/2 and faster lenses (or 300mm+) and are demanding user.