The Nikkorex F
Mamiya produced a camera for Nippon Kogaku (Nikon) similar to the Prismat NP, using a standard Nikon F lens mount. It was introduced in 1962 by Nikon as the Nikkorex F. It was the first camera fitted with the new metal Copal S vertical-travel focal plane shutter, and it beat the introduction of a similar shutter on the Nikon Nikkormat by a full three years. The Nikkorex F, particularly one found in good working order, is very much sought after today by both Nikon and Mamiya collectors.
Later, this same camera from Mamiya can be seen in the Nikon-mount Ricoh Singlex. A version was also marketed in Germany as the Nikkor J. Mamiya also made the Nikkorex Zoom 35