This 35mm L-series lens boasts the brightness of the largest aperture in its class and unrivaled natural delineation. A ground and polished aspherical glass lens element (9th) thoroughly eliminates spherical aberration and distortion. It achieves extremely sharp, faultless image quality only possible with a single focal length lens. A floating mechanism in its optical system corrects all aberrations in the medium and near focusing distances to maintain the lens’ super image quality from the closest shooting distance of 0.3m to infinity. The AF drive system features silent, high-speed AF using rear focus system and a ring USM (Ultrasonic Motor). A wide focus ring permits smooth full-time manual focusing. The non-rotating filter frame affords easy use of circular polarizing and other type of filters. All eleven lens elements are made of environment-friendly lead-free glass.