of all versions of the Nikkor 1.2/55mm.
Apart from a few minor improvements the optical formula (shown above) hasn't been changed during the entire production period. Those minor improvements took place at #220001 & #350011 (see below).
is a Gaussian-I construction, where (seen from the front) the second
and third element and the fourth and the fifth element are kitted. Save
the rear lens , which is a biconvex lens, all others are concave-convex
lenses. On both sides of the aperture blades one finds the negative
elements in opposite position, both covered by positive elements. This
Gauss-I construction makes it possible to design a fast lens with a
focal length of 50-55 mm. The inventor of this design is the German
scientist Karl F. Gauss (1777-1855 ). All early lenses were coated with
a single layer. Nikon states that the S.C-lens (from #250011) was its
first lens ever featuring a multi-layer coating on all lens-to-air surfaces.
Other Nikkors, like the 1.4/35 mm. and 2/28 mm. followed in the same
As mentioned above there were three minor alterations of the optical formula of this lens. In the page above you'll find a cross section of the lens, showing the optical formula. Below you'll find the various dimensions
If you want to clean or repair a lens have a look here. At your own risk, that is!