The 2.1cm F4 Nikon's Rarest Production Rangefinder Lens

Historical Retrofocus Issues
May 1959 Nikon introduced the most extreme available wide angle lens for rangefinder cameras to that date. The lens has outstanding sharpness characteristics and has earned a well deserved superb optics reputation. With a factory record of fewer that a total of three hundred successfully produced it is the rarest and most desirable of Nippon Kogaku collectible rangefinder lenses.

This Nikon improvement and emulation of the Zeiss Biogon F4.5 of a few years earlier benefited from Nikon's application of rare earth derived volcanic salt glass technology and more advanced lens coating technology. The rare earth salt containing elements with their novel characteristic high refractive index and low relative dispersion allowed theretofore impossible correction combinations. The Nikon design is far from just a copy of a Zeiss formulation, it is both 1/2 stop faster and it is sharper. Overall it is obviously a superior optical design.

The optics are so good and retro focus design formulations were so deep into their infancy that despite the obtuse encumberances of having to lose an exposure and lock the mirror up on the original "F" which version was introduce a few months later the same year.that lens was used and recognized for its superior performance.