
The Nikon F4, introduced in 1988 and still used daily by many photographers today, was a breakthrough in that:

The Nikon F3 was an electronic F2, still merely evolution, not revolution. The F was mostly what other companies, like Exacta, had done decades before.

Nikon's first SLR, the F, was just an SP rangefinder with an added prism. Nikon's first rangefinders were merely massaged copies of the Contax and Leica. Nikon's digital SLRs and F5 and F6 are nice, but still none of them, not even the D3, is as earth-shattering as was the F4 at its introduction. The F4 shattered more new barriers and advanced more technology in bigger steps than Nikon had ever done before, or has ever done since.

The Nikon F4 is what brought cameras into this modern era. The indomitable Nikon F4 is the most innovative camera ever introduced by Nikon, or probably anyone.
