70-200mm F/4 L IS or F/2.8 L?

I can't speak for the lens specifically, but I use the 70-200mm vr nikon. The extra stops from the aperture and vr really help, especially since the 350D doesn't have awesome low light capabilities. I have some shots using this lens on a D70 in my portfolio in the Wyclef Jean folder.

If you don't need to capture the action, IS lens will easily compensate for aperture by allowing you to slow the shutter. However if you anticipate taking pictures of moving subjects, IS will not help you.

The non-IS version of f/2.8 is sharp at all apertures. The IS version is a little less sharp at f/2.8, but only if you compare it side-by-side at other apertures and its f/4 siblings.

The IS will only help with camera shake not with subect movement. IS is great for dim light with still subjects but for people the extra stop will be more important to help freeze motion. Also the shallower dof will also help with isolating your subjects. And once you upgrade to the 5D II you can shoot at higher shutter speeds using very high ISOs .

I just realized I didn't really answer the question. I agree with what the other 2 posters said.

I have a 40D with a 70-200mm F4 L is usm and it does fine for everything you mention. Check out Photo Sig website where you can find all kinds of actual photos taken by lens make and type. Then you can see what kind of photos each make or type of lens actually has taken. That may help you in your decision. The last or next to last edition of PCphoto Magazine had an article with photos of theatre productions shot with a 70-200mm F4 L is usm and they were just great.

For a long lens I opted for the 2.8.. IS is nice anywhere but on the long end if I had a choice I would take the extra stop. 2.8 is much more important when shooting subjects farther away ( less benefit from flash ) Also when I really need stability, I can use a tripod, I cant get back that extra stop.

I use the 200mm 2.8 L prime, very good in low-light and gives very sharp images. I think speed counts more than IS for low light. Cost is less than $700.

The 2.8 is very heavy. I would go with it if you plan to shoot with a monopod or tripod. It is hand-holdable, but after 30 or 40 minutes it starts to get pretty old. I have the 2.8 IS -- sometimes I really really need that 2.8 -- but even when I *don't* really need the 2.8, I still have to carry all that weight. I honestly kinda wish I had both. Not that I've got the budget for that kind of redundancy.

I can vouch for the 2.8 being quite sharp wide open. Entirely usable for almost any purpose.

And I would second Nathan's suggestion to at least look at the 200mm f/2.8 (and also the 135mm f/2). If a prime will work for you, they're cheaper and lighter and have excellent image quality.

One solution to your quandry would be to wait a while, until funds allow the f2.8 IS purchase. But I sense the lens is "out of budget" not just due to lack of funds, but also because that's a heck of a lot of money for a lens. Hmm..

I have the f2.8 IS version, and I really got stung. I got mine before the f4 IS version was available, and at inflated Canadian retail prices. Recently, Ive been thinking about getting the f4 IS version, anyways. The f4 is about an inch shorter, a bit narrower, and virtually *half* the weight (roughly 750gm vs 1500gm). It is signif. if you're packing it around for a day.