Canon EF 24mm f/1.4L USM AutoFocus Wide Angle Lens     

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 corner-to-corner delineation is attained from 10 in. (25 cm) to infinity.
Specifications
Construction 9 groups /11 elements
Angle of view 84°
F stop range 1.4 - 22
Closest Focusing Distance 0.25m / 0.82 ft.
Maximum Magnification 1:6.25
Filter Size 77mm
Dimensions (Length x Diameter) 3.3" x 3.1" / 83.5 x 77.4mm
Weight 19.4 oz. / 550g