Offering an impressively wide field of view, the EF 20mm f/2.8 USM from Canon is a well-corrected wide-angle prime also featuring a bright f/2.8 maximum aperture and sophisticated optical design. Four aspherical elements are featured, to limit spherical aberrations and distortion, and two Super UD elements are also used to reduce color fringing for greater clarity. A Super Spectra coating has been applied, too, in order to minimize flare and ghosting for improved contrast and color fidelity. Complementing the optical traits is a ring-type USM for quick and quiet autofocus performance, along with full-time manual focus override, and a floating rear focusing group helps to maintain consistent image quality throughout the focusing range.