70-200 F4 IS Vs 70-200 2.8 non IS

So, I've been doing more night shooting recently and band photography etc. Up until now I've been using my 24-104 F4 but I've got an option to purchase a new lens.

A local store is selling a 70-200 F4 IS for $1449, they're also offering the 70-200 2.8 Non IS for the same price. I know the 2.8 would give better background blur etc and be better in low light, but would the F4 having IS be a better choice?

I've heard the F4 IS is much sharper, even in daylight, than the 2.8 non IS so I'm a little confused. Stretching the budget for 2.8 IS isn't doable (it's another $1200 here) unfortunately so it's onle of these lenses.

What are your thoughts? Most the reviews I've read so far usually end with "it's up to you" and it's not too helpful.

Also, I've been asked to do backup photography for a friend's wedding, the F4 should be fine for that I'm assuming?

I know you probably want to buy local, but you can save up to $300 by purchasing the f/4 IS version on line. http://www.amazon.com/gp/product/B00...edigitalpic-20 or http://www.amazon.com/gp/product/B00...edigitalpic-20.

I use the f/4 IS and absolutely love it. I used it for a couple weddings and it performed flawlessly. That being said, I have never used the 2.8 version of the lens, but with the savings, IS, and overall image sharpness, I would go for the f/4 IS version.

Sorry, I should have clarified, i'm in Sydney Auatralia. If I buy from the US I'll likely lose warranty due to grey import etc :(

If you think you need the 2.8 for the shutter speed (band shots are often in dark places with a ban on flashes), then the IS won't help. If you think the shutter speed will be fine at f/4, then the 4 IS is a great lens, but you need to make the choice between DOF and sharpness.

You can compare blur graphs (sadly just graphs, not emulated output) right here.

I have both the f4 and f2.8 with IS. The driving impetus to get the f2.8 version was for the extra stop to freeze action when used indoors and at dusk and dawn. For the focal length range you are going to find that f4 with 3 or 4 stops worth of IS improves handholdability provided that the subject is not moving fast enough to cause motion blurring. Unless your venues are better lit than what I am familiar with here a 200mm lens without IS is not that useful for a handheld shot unless your camera body has clean output at higher ISO to allow obtaining a high enough shutter speed to avoid camera shake. On a tripod IS not that important anymore.

Thanks all, I just went out and picked up the 2.8. It's heavy considering I've already got a battery grip on my camera etc, but I can't believe the speed of the autofocus, it's insane.

Can't wait to try this thing out at night :)