the 70-200 f/2.8 L IS was my second L series lens purchased, and they still do not disappoint. build and image quality is amazing, and even though its on the heavy side, the images are well worth the extra weight over an inferior telephoto lens.this lens can cover you in most situations, from outdoor nature photography to indoor studio. for outdoor, i also recommend purchasing the 1.4X extender-which increasing the zoom range to 280mm at a constant f/4, still respectable for medium to low light photography with a high iso.while it may be pricey, its more than worth it. if cost is an issue, the 70-200 f/4 L IS or non IS lenses are both very good, but the IS is really worth the extra money, especially on a lens of this length.edited several years later:the price on the 70-200 f/2.8 IS has jumped from $1600 to $2000, despite the release of a version II. While it's still a great lens optically, and still an option if you cant scratch together another few hundred dollars, I hate the idea of paying this much for an old tech lens.

Once you get over the sticker shock of this lens you will be pleased with your purchase. I have had this lens for a few months now, replacing my Sigma 70-200 2.8 and it is a great lens! The IS really helps catch those shots that I missed before. The Sigma lens was good, but the Canon 70-200 2.8 consistantly delivers everytime.

Very happy with the results. I added the extender to my Canon 70-200 2.8 lens and shot a soccer game with it. Great results. I didnt really see any slow down to the autofocus. It did push me up from 2.8 to 5.6, so more than the 2 stops I thought it would go to - but on a sunny day outdoors, it didn't impact me.

I had the 70-200/4.0L but wanted to get to only three zooms all at 2.8. I've never felt IS was needed. Well, I got this lens for Christmas and have changed my mind. With the 5D's low noise at high ISO's this lens opens up new ways of shooting with availble light and not having to keep changing out to fast primes.One of Canon's great lenses, you'll not regret it.

Nice addition to my lens collection, but it only works with certain lenses. It works great with my 70 -200 2.8 canon lens.

I've tried the generic extenders and they can't compare. With my 70-200 2.8 even being restricted to center focus, it is still fast and accurate. Get the CANON, don't skimp!

Canon Ex-2X extender Excellent extender for the fast 2.8 Canon 70 to 200 lens. Great to hand hold and get sharp images, with proper camera uses.

Worked well with my Canon 70-200 2.8 IS lens on a recent African Safari.