The Nikon FM (Photo) introduced at the 1977 "Nippon Camera Show" went on sale in May of the year.
At that time, Nippon Kogaku K.K. was trying to adopt an AI system for a SLR camera TTL metering system — a breakthrough that never really happened.
As it turns out, the Nikon FM became a leading product.
The AI, or "Automatic maximum aperture Indexing" system renewed, for easier TTL metering, the aperture-coupling device between a Nikkor lens and camera's exposure meter which was basically established for external metering system.
Its designers strove for backward compatibility with previous models and a coupling device to cope with the latest technology.
This made the camera historic for Nikon.
Following this, the Nikon F2 Photomic became the Nikon F2 Photomic A, the Nikomat FT2 became the Nikomat FT3 (see Part 6.), and the Nikomat EL (See Part 7.) became the Nikon EL2 (See Part 8.).
All the older models were renewed with the change to coupling devices (as mentioned in the earlier issue, the NikonEL2 metering system also marked a great change).
The Nikon FM was, above all, entirely new and designed from scratch.
It was a Nippon Kogaku's solution in line with the trend towards smaller SLR's and for request for a camera a step lower than the Nikon F2 request by oversea distributors mainly in the U.S.