The Nikon SP was Nikon's last and best interchangeable-lens rangefinder model, introduced in the late 1950s.

Like earlier Nikon rangefinders, it used the lens mount/focussing helical of the Zeiss Contax. That's why I was able to use it with the wonderful 21 mm Biogon lens shown.

This photo was made with my Soligor 66 using the "painting with light" technique. I used an open shutter, and a handheld flash unit. I flashed 8 times, moving the flash around behind the camera. You can see the 8 "catchlights" in the lens.

This camera was intended to be a direct competitor to the Leica M3, and it had areas of genuine superiority to the Leica, most notably the viewfinder.

It had a two-window viewfinder system:

• The main viewfinder/rangefinder window was life size, optically neutral, with parallax-corrected framelines for 50, 85, 105 and 135 mm lenses. The framelines are unusually precise. The unique feature of this viewfinder/rangefinder was its optical neutrality, which permitted the photographer to keep both eyes open, a big plus for action photography.
• The secondary viewfinder was for use with the wide-angle lneses. The overall frame corresponds to the 28 mm, and there's a fixed frameline for 35 mm lenses.

The SP introduced the titanium focal-plane shutter later used on the Nikon F SLR

I got a fabulous deal on this camera, paid $75 for the body with 50 mm f1.4, 85 f2 & 135 f3.5 Nikkor lenses. It was cheap because it was busted...it had been dropped, and the rangefinder prism had separated. When you would look through the finder, all was black except for the frame lines and the rangefinder spot. Fortunately, I was able to disassemble it and re-cement the rangefinder prism, and it worked great for several years for me, until I wound up selling it in a weak moment.