Canon EF 16-35mm f/2.8L USM Ultra Wide Angle Zoom Lens for Canon SLR Cameras (Discontinued by Manufacturer) Micro UltraSonic Motor (USM) f/2.8 constant maximum aperture Super Ultra-low Dispersion glass; inner focusing; aspherical lens; full-time manual focus EF mount; ultra-wide zoom lens 16-35mm focal length EF mount; ultra-wide zoom lens Super Ultra-low Dispersion glass; inner focusing; aspherical lens; full-time manual focus 16-35mm focal length f/2.8 constant maximum aperture Micro UltraSonic Motor (USM)