Description Wide-angle zoom is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 25.6-56mm equivalent focal length range. Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range. An Optical Image Stabilizer helps to minimize the appearance of camera shake by up to four shutter speed stops to better enable working in low-light conditions and with slower shutter speeds. A ring-type Ultrasonic Motor (USM), along with an internal focusing system, is employed to deliver fast, precise, and quiet autofocus performance as well as full-time manual focus override. Rounded nine-blade diaphragm contributes to a pleasing out of focus quality that benefits the use of shallow depth of field and selective focus techniques.
