(requiring a double-twist of the lens aperture ring on mounting), and its viewfinder had a choice of Type J or Type A fixed focusing-screens. Nikkormat ELW The Nikkormat ELW, manufactured from 1976 to 1977, was an EL modified to accept the Nikon AW-1 autowinder, providing motorized film advance at up to two frames per second. The ELW also expanded the automatic shutter speed range to eight seconds, and its viewfinder was fitted with a new standard focusing screen, the Type K (see the Nikkormat FT2 above). Nikon EL2 The Nikon EL2 was manufactured from 1977 to 1978 and was essentially identical to the ELW, but with the addition of instant response silicon photodiode light meter sensors and support for Nikkor lenses with the new Automatic Indexing (AI) feature (see the Nikkormat FT3 above). The EL2 also abandoned the Nikkormat name (the Nikkormat FT3 being the last of the Nikkormat line) which had distinguished these cameras from the better known Nikon-badged models. The Nikon EL2 was replaced after a year of production by the Nikon FE. Design history In 1959, Nippon Kogaku released its first 35 mm SLR, the professional level Nikon F. The F combined every SLR technological advance available in 1959 (automatic diaphragm lenses, instant return mirror and eye-level pentaprism viewfinder) into an integrated package with mechanical durability and reliability, plus optical quality. It also offered the most complete system of accessories in the world, including interchangeable viewfinder heads, viewfinder screens, motor drives, flashbulb units, bulk film backs and eventually over fifty Nikkor lenses. The F quickly became a preferred 35 mm camera among professional photographers, especially photojournalists and amateurs who could afford them. However, the professional SLR market is a small market. The Nikon F with Nikkor 50 mm f/2 lens had a list price of US$359.50 in 1959 when new cars sold in the US$2500 range. Many amateur photographers could not afford Nikon cameras. Nippon Kogaku had tried offering a consumer grade camera-brand; beginning in 1963 the Nikkorex SLR was made by Mamiya but marketed by Nippon Kogaku and its distributors. Initially these cameras had fixed lenses and built-in metering, but in 1963 the Nikkorex F (made by Mamiya) was introduced; this was fully compatible with Nikkor F-mount lenses and had a look similar to the Nikon F style, though it was a larger camera. Despite reasonable quality in the later production, the Nikkorex brand was a