The Classic 5cm F1.1 Rangefinder Lens

This massive lens which was a culmination of all of Nippon Kogaku's optical expertise in the mid 1950's was, perhaps, its most technically bombastic triumph. This huge lens had to, on introduction, disturb many of Nikon's mechanical body designers. The mechanics of the helical focusing mount were never imagined in advance to be able to support such a massive piece of glass and metal that rivaled the camera body itself in weight. At more than 3/4 pound the lens was in time recognized as capable of permanently distorting the helical rangefinder mount and leading to permanent focusing errors on the part of the camera body that suffered the damage.

The lens employed advanced, for that time, coatings, rare earth bearing glass elements, split thin elements, in a nine element-six group array that was not only unrivaled in light gathering power but maintained extremely respectable sharpness throughout its nearly 10 stops (a factor of 500 approximately) of light exposure range. The aperture is a mechanically complex 12 blade very circular array that renders excellent brokeh. In short, it was a collection of the very best technology that Nippon Kogaku was able to offer at the time.

Fewer than 1050 ( 836 in Nikon BM and 211 in Leica Screw Mount [LTM]) of these were manufactured during the almost three years until the summer of 1959 when the external mount version was introduced. The external mount version, ironically is even more massive at 7/8 pound (400 ounces) but the extra mass is dedicated to providing with the lens superstructure the focusing helix that the lens rides and loads, rendering it far more structurally stable as it is supported by the front structure frame of the camera body rather than just by the far more delicate focusing helix mechanism which is obviously not capable of bearing such brutal mechanical loads. During the next five years or so an additional 1,547 of these beautiful optical monsters were manufactured with the far more mechanically stable external bayonet mount.