The Nikon AF-S 50mm f/1.4G lens is a fast, fixed focal-length Nikkor lens that incorporates the built-in Silent Wave Motor (SWM) enabling smooth and quiet autofocus with Nikon DSLR's including the D40, D40x and D60. The improved optical system delivers fantastic image quality minimising both flare and chromatic aberration while the use of a circular aperture diaphragm means out of focus background blur appears more natural. During focusing all the lens groups shift but the front element and filter mount do not rotate and the barrel length does not change, making it an ideal lens for close-up photography or when using SB-R200 Wireless Remote Speedlight units. The lens has has two focus modes, M/A (manual-priority autofocus) and M (manual focus). When mounted on a DX-format SLR, the picture angle is equivalent to a focal length of about 75mm in 35mm format.