The EF 16-35mm f/2.8L III USM from Canon is a workhorse wide-angle zoom and a member of the well-regarded L series of lenses. Featuring a series of specialized elements, this lens utilizes a trio of aspherical elements and two ultra-low dispersion glass elements to control a variety of aberrations for high sharpness and clarity. Complementing its optical prowess, a ring-type Ultrasonic Motor offers fast, smooth, and near-silent autofocus performance, further benefitted by full-time manual focus operation and an internal focusing design. Wide-angle zoom 16-35mm lens is compatible with full-frame Canon EF-mount DSLRs and APS-C-sized models that will provide a 25.6-56mm equivalent focal length range. Two large-diameter glass-molded dual-surface aspherical elements and one ground aspherical element help to minimize distortions and spherical aberrations throughout the zoom range in order to maintain edge-to-edge sharpness and illumination. A Subwavelength Coating (SWC) and an Air Sphere Coating (ASC) have been applied to lens elements to reduce backlit flaring and ghosting for maintained light transmission and high contrast in strong lighting conditions. As a member of the esteemed L-series, this lens is sealed against dust and moisture for working in inclement environmental conditions. The 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.