50mm focal length and maximum aperture of f/1.8 Minimum focusing distance of 1.15 ft. (0.35m) and a maximum magnification of 0.21x 80mm effective focal-length on APS-C cameras, 50mm on full-frame cameras Stepping motor (STM) delivers near silent, continous Move Servo AF for movies and smooth AF for stills The lens features a metal mount has a rounded seven-blade aperture and plastic body