Canon EF 20mm f/2.8 USM Wide-Angle Fixed Lens Focal length and maximum aperture: 20mm 1:2.8 Lens construction: 11 elements in 9 groups Diagonal angle of view: 94 Degree Rear focusing system with USM focus adjustment Closest focusing distance: 0.20m/0.66 ft. EF mount; wide-angle lens Floating system; inner focusing; full-time manual focus 20mm focal length f/2.8 maximum aperture Ring-type UltraSonic Motor (USM) Lens not Zoomable