Canon EF 17-40mm f/4L USM Ultra Wide Angle Zoom Lens with Case and Lens Hood - USA
Excellent wide-angle lens
Pros: Easily Mounted, Easily Accessible Controls, Strong Construction, Clear Glass
Describe Yourself: Hobbyist/Enthusiast
Best Uses: Travel, Photojournalism, Fun
Bottom Line: Yes, I would recommend this to a friend
I used this lens for close to two years, with no complaints whatsoever. I stopped using it when I gave it to my mother, who still uses it quite a bit.
The image quality is pristine, as is usually the case for Canon's L lenses, and the autofocus is similary quiet and responsive. It does not have any visible barrel distortions that I have seen, but I have also not used it on a full-frame camera, only on a Digital Rebel. In spite of the crop factor, it is still wide enough to be a bit of a challenge to compose with, but when it works, it works well.
For the money, this is an excellent lens.