Quote Originally Posted by 2484Stryker View Post
When I compared the two lenses, I changed both to 50D. Are you saying that the 17-40 was only tested on the FF and so even when I selected 50D it still showed me the same images from the FF?
Sorry, no. I didn't check to see that a 50D test was available - most EF lenses in the tool only have FF shots.

Still, I'd take the extra stop and IS. The 17-55mm is an excellent lens, IMO the best general purpose zoom for APS-C.