Canon EF-S 17-55mm 1:2.8 IS USM

The Canon EF-S 17-55mm f/2.8 USM IS is not a perfect lens but it lives quite well up to the very high expectations of the user base. The resolution figures are among the very best seen so far for an APS-C standard zoom lens. The center resolution is nothing short of outstanding and the even borders can keep a very good to even excellent quality level. The distortion characteristic is quite typical for a zoom lens in this range (pronounced barrel distortions @ 17mm, moderate pincushion distortions @ 55mm) whereas CAs are unusually moderate. Unfortunately vignetting is a weak spot of the lens peaking around 1EV at f/2.8 throughout the range. It's not a show stopper but a little annoying nonetheless. The build quality of the lens is pretty good but in relation to the price tag of the lens Canon should have used a little less plastic - finally even the much cheaper EF 70-200mm f/4 USM L features a magnesium-alloy shell. Probably a marketing decision to keep professionals away from APS-C DSLRs. All-in-all the EF-S 17-55mm f/2.8 USM IS is clearly a level up from the other Canon standard zooms - a highly desirable lens though the pricing may rise a few question marks.

The Canon EF-S 17-55mm f/2.8 USM IS is not a perfect lens but it lives quite well up to the very high expectations of the user base. The resolution figures are among the very best for an APS-C standard zoom lens. The center resolution is generally excellent even on the EOS 50D and the borders can keep a very good quality level. The distortion characteristic is quite typical for a zoom lens in this range (relatively pronounced barrel distortion @ 17mm, moderate pincushion distortion @ 55mm) whereas lateral CAs are unusually moderate. Unfortunately vignetting can be an issue at f/2.8 and the quality of the bokeh (rendering of the out-of-focus blur) lacks greatness in critical situations. The build quality of the lens is pretty good but in relation to its price tag Canon should have used a little less plastic - finally even the much cheaper EF 70-200mm f/4 USM L features a magnesium-alloy shell. All-in-all the EF-S 17-55mm f/2.8 USM IS is clearly a level up from the other Canon standard zoom lenses albeit a pricey one.