The EF-S 17-55mm f/2.8 IS USM offers image quality on a par with Canon's highly regarded L-series lenses. It has a large maximum aperture which, combined with higher shutter speeds can minimize subject motion blur. Shallow depth-of-field separation of a subject from its background is much easier to achieve and the f/2.8 maximum aperture allows a bright finder and extremely precise focusing with f/2.8 compatible AF sensors. The internal stabilization has a sharpness benefit equivalent to a three-stop faster shutter speed, making this lens outstanding in low light situations. Smaller and lighter than lenses of similar specifications, the EF-S 17-55 mm f/2.8 IS USM lens has a 35mm equivalent focal length of
