Canon 70/200 f4 IS L vs. Sigma 70/200 f2,8

I plan to buy a new telezoom for my 5D. I´m almost decided for the 70/200 f4 IS, but I´m also considering the Sigma 2,8.
One year ago I had the Canon f4 (non IS) but I sold it because I didn´t make any sharp picture under 1/500, so I think I need the IS.
What do you suggest ?

I think you just answered your own question.

is only stops camera shake and not action.
I dont see how you didnt get any photos with 1/500 that where not sharp unless you where not focusing on the proper thing. f4IS and sigma 2.8 will be the same at 1/500 at that speed IS is not even doing anything really for you since you are well up there in shutter speed over the focal length

If I could aford a 5D I would have a Canon 70-200mm 2.8 IS, but I cannot. The Sigma 70-200mm 2.8 produces great images. It depends on how deep your pockets are...

Interestingly, I have discovered that the Sigma 70-200 AF speed just does not seem to be as fast as my other three Canon L's. This is even after sticking it on a 1D. It's a decent lens colors are great, decently sharp, and I got mine at an awesome price so I won't complain, but it's definitely no L. Still gonna keep mine, it's good value.

I have the Sigma and love it, but if your problem is that you can't get
sharp pictures with the Canon that is lighter, I don't think it is the right
choice for you.
I would go for the Canon f4 IS instead.

Are you sure its shake and not motion? 1/500 seems a decent shutter speed to avoid shake.

kram wrote in post #2069897
Are you sure its shake and not motion? 1/500 seems a decent shutter speed to avoid shake.

I do mean shake, not motion, at 500 was Ok, but under 500 was not good.
Later on I bought a 70/300DO IS, with this lens I had not blurr, but the IQ was not very good, so I sold it in order to buy the 70/200 f4 IS (the 2,8 IS is to expensive and to heavy for my taste). Now I´m waiting for the arrival of the f4 IS, but in the meantime I´m hesitating between this one and the SIgma.

If you can't hold it steady enough below 1/500, maybe you should get a tripod or monopod. I can shoot mine down to 1/60 second pretty well. It's not always perfect, but it can be done.

jalafer wrote in post #2070237
I do mean shake, not motion, at 500 was Ok, but under 500 was not good.
Later on I bought a 70/300DO IS, with this lens I had not blurr, but the IQ was not very good, so I sold it in order to buy the 70/200 f4 IS (the 2,8 IS is to expensive and to heavy for my taste). Now I´m waiting for the arrival of the f4 IS, but in the meantime I´m hesitating between this one and the SIgma.

WOW...you are getting blurry pics from shake at 1/500
what are you jumping up and down as you take the pics

Personally, if you are having issues with camera shake at 200mm with a 1/500 shutter speed, then working on techniques of steadying your camera may be the best thing. No feature or equipment can make as much improvement as good technique. Throwing money at a problem may just lead to a more expensive problem.

As for the lenses. The IS gets you more stops to prevent blurs from hand shake, but it's still going to give you a dark view finder and a deeper DOF than a f2.8. Plus some cameras focus faster with a f2.8 lens than a f4 lens. IS, as mentioned above doesn't prevent blurrs from moving subjects shot at low shutter speeds. Being conservative, you should be able to shoot at 1/200 sec shutter speed with a 200mm zoom on a full frame camera.