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 handheld photography in comparatively dim light without a flash or tripod. At the wideangle 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.
In addition, the lens has a USM drive mechanism for faster and quieter AF operation, and the pulse control diaphragm (EMD) ensures precise aperture control.
The IS system is composed of a pair of gyro sensors to detect vertical and horizontal motion and a microprocessor that compensates for it by shifting special lens elements in parallel with the perceived movement.
The internal focusing mechanism allows the front of the lens to remain stationary and to easily accommodate specialty filters, such as polarizing filters.