Quote Originally Posted by cxr


...there are many reviews saying that the image quality of the 15-85 in nearly the same as the 17-55.



In terms of sharpness, yes. But, being a >5x zoom lens, the 15-85mm suffers significantly more from distortion than the 17-55mm (and of course, the 18-200mm lens which elmo_2006 mentioned is even worse).


It does really depend on what you mean by 'walking around'. If you actually mean walking around on the street or on a trail, taking daytime pictures, then the 15-85 will be a good choice. If you mean 'walk-around lens' in the sense of the lens that stays on your camera most of the time, it depends more on what you take pictures of, and what other lenses you have or plan to get. If you'll shoot indoors and want to use natural light, the 17-55mm f/2.8 is a better choice. If you don't mind using a flash (don't use the built-in pop-up flash, please!) and don't need the out-of-focus blur capability of f/2.8, you can get the 15-85mm plus a 430EX II flash for about the same cost (a little less, actually) as the 17-55mm lens.