	In 1981 Canon introduced a self-contained autofocus lens, the 35–70 mm AF, which contained an optical triangulation system that would focus the lens on the subject in the exact center when a button on the side of the lens was pushed. It would work on any Canon FD camera body. Nikon's F3AF was a highly specialized autofocus camera. It was a variant of the Nikon F3 that worked with the full range of Nikon manual focus lenses, but also featured two dedicated AF lenses (an 80 mm and a 200 mm) that coupled with a special AF viewfinder. F3AF lenses were only supported by the F3AF, the F501, and the F4. Nikon's later AF cameras and lenses used an entirely different design.