The Canon EF 16 mm to 35mm Lens features a ring-type Ultrasonic Motor (USM) that has a quick, silent autofocus and full-time manual focus override. It incorporates Optical Image Stabilization technology and automatically detects normal shooting or panning motion. This lens is sealed with waterproof and dustproof elements that protect it from harsh weather conditions. Also, it has an f/4 to f/22 aperture.