The Canon EF 28-135mm f/3.5-5.6 IS Lens is a compact and lightweight standard zoom lens that offers superior optical performance, plus a built-in Image Stabilizer. The IS system reduces the possibility of blurred photographs caused by camera shake, which allows for hand held photography in comparatively dim light without a flash or tripod. At the wide angle end of the zoom range, the equivalent shutter speed gain is approximately 1.5 stops while at the telephoto end, it is approximately 2 stops. Also, the lens has a USM drive mechanism for faster and quieter AF operation, and the pulse control diaphragm (EMD) ensures precise aperture control.