Is 5D AF better than 20D's? (was: 20D, 5D or 1DMkII for dance and theater?)

I currently have a 20D and I've been shooting more dance and performance venues lately. I've started to earn a little extra cash from this and I hope to carve out a little niche and do this part time.

I'm happy with the image quality and ISO performance of the 20D, but I'm a little frustrated with the AF Servo performance. I use CF4-3 and for static subjects single shot AF works ok, but when a performer is moving I want to use AF Servo end up with about 50% reject rate for poor focus. I've tried just the center focus point, as well as using all focus points. I use only prime lenses (50 f/1.8 mkI, 85 f/1.8 and 100 f/2).

I'm considering using my end-of-year bonus to move to the 5D if it has better AF performance than the 20D. The quieter shutter would be a plus.

I know that the 1Dmk2 and -N have better AF performance, and for less than the cost of a new 5D I can get a used 1DmkII, and for a little more than a 5D+grip I can get a new 1dmk2N. But I don't really need the FPS or build quality, and since this will be my only camera I'm not real excited about the weight of the 1D... at least I can remove the grip on the 5D.

So I'm asking those who have moved from the 20D to the 5D if there is a significant improvement in the AF performance? Or should I consider just the 1Dmk2? I've done a lot of searching but I haven't seen the AF perfomance of the 5D compared to the 20D or 1DmkII.

I realize the successor to the 20D will probably be announced next month, but it'll be a couple of months before that's available and there's no guarantee that it will have significant improvements in AF. Plus, I have a buyer for my 20D now.

Thanks.

Changed the subject to match the main question. Good question: anyone can answer that?

I'm very happy with the AF on my 5D. I haven't used it to shoot alot of moving subjects in low light but I have done a fair bit of low light static subjects and it is finding the focus very quickly.

I might try and do a test between my 5D and 20D on something moving in low light.

I can't judge the capabilities of the 20D, but I'm very happy with the 5D's AF. Very consistent & accurate.

I haven't timed it to the split second, but my 5D definately seems to AF faster than my 20D.

My 5d finds and lock focus better than my 20d ever did AND is WAY faster than my 1dmkIIn-but i think my 1dmkIIn just makes extra sure its focused

Funny...I would think that a 1DMkII(N) would put a 5D and 20D to shame, as far as focus speed goes.

Of course, that depends on your lens, too.

It does when using servo and focusing outside the spot-meter circle. Inside or adjacent to the circle, the 5D is pretty close to the 1D II with good focus-point density in the center. In low-light, the 5D and 20D both have a 1/2 stop advantage in minimum light for AF according to specs.

In practice, I found a little advantage with the 5D compared to my 1D II in very dim light. It was there, but when I tried several times to focus on the "almost impossible" with both cameras, the 5D would hit on 8 of 10 tries, and the 1D II, maybe 4 of 10. On the moving subjects that I shot (air shows, birds in flight, field sports), they were comparable. But I don't shoot trackside for NASCAR or F1 so I don't get the super-fast action where the 1D II should, by all rights, excel.

A similar problem (shooting hockey, low light, fast action) led me to upgrade from the 20D to a 1DmarkIIN. See >>>this thread<<< and >>>this one<<<. Suggest you look carefully at your shots to see if the 20D is trying to focus on the wrong AF points, as mine did.

the problem only occured for me in low light shooting (exposures like ISO1600, 1/400, f2) -- in regular shooting the 20D did quite well for me.

the 1D solved the problem. didn't try a 5D. good luck.

Can't speak for the 20D. But on the 5D, if A1 focus is selected and only one focus point is selected, only that focus point will track the subject. Unless, you set CF-17 to "expanded" in which case if the center focus point is selected along with CF-17-1, it will activate the 6 "invisible" focus points as well, giving you 7 AF points within the spot-metering circle with which to track moving subjects. This function is similar to what's available on the 1D II, but is limited to the spot metering circle area and the hidden focus points plus the center point.

That's about EV-6 if I'm reading my chart correctly. Fairly low light. Can't say that I've tested servo/predictive focusing at that level.

So if the 5D is limited like that. How does the 1dMKII counteract or how does its focus differ than the 20D and 5D. Im gettin a 1-series soon and must admit that I have not yet read the manual : /

If you get the 5D and grip do you really think you will be taking the grip off and on? Get the 1D Mk2n.

Excellent point. Since I'll have to fund the upgrade with the sale of my 20D, the replacement will not only serve duty photographing performances but also be my recreational (and family snapshot) camera. The form factor of the 5D is better suited to that. Plus, the 5D shutter is quieter than both the 1DmkII and the 20D, which is less distracting in the theater.

But better AF speed and accuracy over the 20D is what I want. I'm confident that the 1DmkII is much better than the 20D, but if the 5D AF is almost as good as the 1DmkII, then the physical size, shutter noise, and price make it more a more attractive option for me.

From what I've read above, it appears that the 5D AF is significantly better than the 20D, and approaches the 1DmkII in low light situations. I'm sure it won't track a F1 car through a chicane, but on the other hand, my 20D was able to take quite a few good images of the USAF Thunderbirds as they flew overhead at 400kts last summer.

Dave --

the 1D mark II N (and I think the non-N as well) has a personal function setting that sets "quiet operation" -- the mirror moves more slowly. The camera is noticeably quieter with this set, but you loose high-speed shooting.

the 1D...N allows AF point expansion, in which if a single AF point is selected the camera uses that and the 7 AF points immediately surrounding it. This seems to be most helpful for erratically moving small objects like birds. My experiments with it at hockey shooting lead me to leave expansion off -- it focusses on the nearest thing rather than exactly on what I'm pointing the center AF point at.

Wow, is the shutter sound really that loud?