I looked at this lens today and took a picture with it Wide Open. Out of curiosity I also tried out a 17-85 IS lens to see the big difference between the two lenses. The build of the 17-55 was a little bit better then the cheaper 17-85 but the images in the store, the 17-55 at f2.8 and the 17-85 at f3.5 both look almost exactly the same. Yeah I know these are not the same lenses and the constant f2.8 of the 17-55 is a good thing but other then that I really can't tell the difference and feel the 17-55 is over priced. But here are two comparison shots for you. They suck I know but just an idea. first one is 17-55 second is 17-85 both with IS on.
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