This lens uses the EF-S mount which is only compatible with Canon Digital Rebel, Digital Rebel XT, 20D, and 30D cameras. Equivalent to a 28-135mm lens, this new EF-S lens brings true wide-angle to tele coverage to EOS 20D and Digital Rebel shooters. It has Canon's Image Stabilization system, allowing safe hand-holding at speeds up to three stops slower than otherwise possible. And of course, it's optically optimized for digital SLRs. A ring-type USM means both fast and silent AF, as well as full-time manual focus when in the AF mode.