This is the only EF-S lens that I own. It will probably be the only EF-S lens that I ever own. Itís that good. My normal cameras are the Canon 1DsMKII, the 5DMKII and the 1DMKIIN that wonít mount this lens, but I have a 40D and this lens is great on an APS-C camera. This lens is probably the only reason I keep the 40D around. Itís just that good. The combination is great for shooting family events, chasing grandkids, and for casual day hikes.
The 17-55 focal length on an APS-C (1.6 crop) camera gives a field of view (FOV) equivalent to that of a 27-88mm lens on a 35mm format (Full Frame) camera which is almost an ideal range for a walk around lens. Add to that a constant f/2.8 aperture and 3 stop image stabilization and youíve got a wonderful lens for some serious photography.
I bought this lens specifically for family photography, low-light indoor venues, and as a walk-around lens. I take lots of photos of my grandchildren and this lens appealed to me for that use. Iíve owned it for a couple of years now and itís been nearly perfect for those uses. In the last couple of years, Iíve also used it for glamour and landscape photography (see the examples with this article) and found it quite useful for those purposes as well.
The AF is fast and accurate and the Ring USM allows for Full Time Manual Focusing. The focus ring is small, but smooth and well damped. The focus ring is larger and operates quite smoothly. Minimum focusing distance for this lens is 1.15 feet (0.35 meters) and the minimum aperture is f/22.
The lens weighs in at 1.4 pounds (645 grams) which is only slightly less than that of the 24-105 f/4 L IS. The optics for this lens consists of 19 elements in 12 groups which include 3 aspherical elements and 1 Super UD (ultra-low dispersion) element. Canon also notes that the lens features their Super Spectra lens coating for flare control, and indeed, flare is well controlled even at the widest focal length. Chromatic Aberrations (CA) are also well controlled though I have noted some minor fringing is some very high contrast situations.
The 17-55 communicates distance information to the camera for E-TTL II exposure settings. The 77mm filter size is consistent with Canonís L series zooms, which facilitates sharing filters with those lenses. Unfortunately, the lens is not provided with the EW-83J lens hood. The hood much be purchased separately, but a lens hood is essential for all lenses, and especially wide-angle zooms like the EFS 17-55 f/2.8 IS.
If you primarily use a Canon 1.6 crop camera such as the Rebel or XXD series cameras, I think this is an essential lens for your camera bag. Itís sharper than the 16-35 f/2.8L with the advantage of IS. This isnít a cheap lens, though, retailing right at $1000 USD at the time of this writing.
Some photographers have reported dust issues with this lens, specifically a build up of dust particles behind the front element over time. Iíve never experienced this and it would take a huge amount of dust to actually degrade the image quality. Dust buildup is common in all lenses, but especially zooms and the 17-55 is not exceptional in this regard.
The bottom line is that this is a sharp, well featured lens and only lacks being an L because of the build quality and the fact that itís an EF-S lens designed for a crop body.