Yes it is a big, heavy lens, but this is the 2nd most important “L” lens you should purchase. At 2.8, it is solid in low light. With a focal range of 70-200mm, it is outstanding for portraits on both full frame and 1.6x crop cameras. Very good for sports, weddings, receptions, parties. In fact anything you want to shoot that is 12 – 50 feet away, this would be a lens you will want to consider. The glass is also very “clean”, when I say that I mean the colors are luscious and beautiful, visibly so more than other lenses. Image Stabilization makes it that much better in low light or for longer distances.

I know it is ridiculously expensive, but in terms of its focal range, aperture and quality- you won’t find a better lens anywhere.

However, because it is so expensive, you may consider the Canon 70-200 f4 which runs just under $600. Its an f4, and lacks IS, but is also an excellent lens.