This lens is an EF 24 mm 1.4 L USM.See full specification
Lens construction: 11 elements in 9 groups
Diagonal angle of view: 84°
Focus adjustment: Rear focusing system with USM
Closest focusing distance: 0.25m / 0.8ft
Filter size: 77mm
Professional wide-angle lens with an ultra-large maximum aperture of f/1.4.This is the first EF lens to employ both a replicated aspherical lens element to suppress distortion and spherical aberration, and a UD lens element to correct lateral chromatic aberration. Thanks to the floating construction, excellent comer-to-corner delineation is attained from 25 cm to infinity.