Some advice on a two-body setup....

I was just thinking about my camera setup and wondering how I should configure it for events coverage. I make the most use of my standard zoom (24-105 f/4L) so that will go on my 5D. In fact, if I had to, I'd shoot the entire event with nothing more than that setup! So the choice is what should I put on my second body, which is a 350D.

It's going to be a telephoto, so I looked at my Sigma 70-200 and Canon 70-300 IS. Both are fine lenses, but I don't trust the 350D's focusing performance with long AND large-aperture teles, so I did some testing. The focus is very inconsistent with the Sigma, so I stopped it down. Larger DOF eats up the focusing errors, but it is still inconsistent. Then I realized focusing takes place wide open, so that is a problem in and as of itself. Don't get me wrong - I'm not blaming the lens, because it is awesome on my 5D. Focus is dead-on accurate even in AI Servo with subjects jumping all around, and I LIKE that. I'd put it on the 5D, but in my current configuration, the 24-105 is already paired to the 5D.

I switched to the 70-300 IS, and constrained by the smaller physical maximum aperture, the focus is very much more consistent, to a standard that I like.

So... that means 5D + 24-105, and 350D + 70-300 I guess, even though I would like to use the Sigma thanks to the larger aperture. Does anybody have any other suggestions or recommendations? I'm aware upgrading to a second body with f/2.8 precision sensors (like the 5D's AF engine) would solve this problem, but I think I've overspent my budget already and would like to get more out of my existing setup. Critical focus and focusing precision is important, especially for a tele that will be used for portraits. Or should I go with one body and change lenses, despite all the downtime that entails?

BTW, not a professional - just a volunteer trying to get more out of his gear. That's the other reason I'm not willing to spend $800 on a new body, because while I'm generous enough with my time and skillset, I can't be THAT generous with the cash.

Events - but what kind of events? Makes a difference in lens mixes. Some things I use the 24-70 on the 5D, 70-200 on the 20D; others it's the other way 'round. It all depends on what working distance I'd need/get.

I use a Sigma 70-200 f2.8 paired up with an EOS 350D covering Polo and have no problem with focusing even fast moving objects in groups wide open. Maybe check the camera?

I'd have the 24-105 on the 5D and 70-200 f/4L on the 350D. Both are superb lenses, but I think however that 24-105 on the 350D and 17-40 f/4L on the 5D would be fine, unless there's alot of vignetting on the 5D with 17-40 f/4L.

I used my 350D & Sigma 70-200 this week at my son's school production with no focus issues (and we all know how great the lighting is in school halls don't we?)

I wish I had a second body so I didn't have to swap the 17-55 and 70-200!

Ah, these are more like corporate events, you get a mix of speakers, people wandering around, some presentations. And generally you get to walk around and take photos of people doing silly things usually I get to shoot at short range.

From experience I find I could do 90% of them with a standard zoom, but it's nice to have a telephoto. It's a real pity that the 350D does not focus as accurately as I would like with f/2.8 tele's.

I did think about 5D/17-40 and 350D/24-105, hmm.. actually that sounds quite interesting. Must think a bit more

scott: actually, you've reminded me of a very good point. My focus-check tests were conducted indoors at short range, and DOF is very shallow at short range. It highlights the limitations of the 350D, but at the same time you've reminded me that these aren't necessarily representative of the conditions I will be shooting in - I'd use the tele when, well, I need to shoot stuff like, further away from me

Maybe I'll see if Canon comes up with a good 40D... ahh, the temptation yet again

DING DING DING.... We have a winner!!!! Well at least what I would do.

But I don't have a f4L!

Besides Dante.. former or latter setup? (5D/24-105 or 5D/17-40?)

I expect my main event set-up to be 5D/24-105 and 30D with whatever I need that day. I bought the 17-40 for ultra-wide on the 5D and also to give me wide coverage on the 30D should the 5D fail mid-wedding. 24mm on the 1.6x body just wouldn't give me enough width for some large group shots. So that's more of a failsafe.

When I shot Nikon I used a 17-55 and 85/1.4 most of the time for weddings, so I won't be surprised to see either the 50/1.4 or 135/2 on either body a fair amount, with the 70-200/2.8 for the ceremony if I can't get close in church (ie. most of the time).