Review of the Nikon NIKKOR-S Auto 1:2 f=5cm Nippon Kogaku Non-Ai Lens (50mm f/2).
This is the old 5cm focal length f/2 Nippon Kogaku lens sold with Nikon cameras during
the early sixties and, curiously, the front element appears to be flat. It was introduced
in 1959. This is a Nikkor-S which means it has seven elements (S for Sept). In 1964,
the optical formula was changed to have six elements making it become a Nikkor-H (Hex).
The reason the front element is flat (very slightly concave, really) is because, at this time, Nikon were unable to make a standard
50mm lens and had to improvise by adding this special front element thereby changing the angle of view of the light
going to the lens elements behind it. With the
Nikon NIKKOR-H Auto 1:2 f=50mm Nippon Kogaku lens,
Nikon solved all their problems and did not need the flat front element.
This lens is made in Japan. It has distance markers in feet only and an
infrared focus index. It is marked Patent Pending
and stops down to f/16 using a six-bladed diaphragm. This is a pre-Ai lens meaning it
will not work on most modern Nikon cameras even though, technically, the lens mount
has not changed since its introduction in 1959. It is single-coated and has depth of
field and focus scales.
The performance of this lens is a worse than that of the
Nikkor-S Auto 1:1.4 f=50mm Nippon Kogaku pre-Ai.
This lens is softer in the center than in the corners! This has been verified several times on two samples.
Bokeh-wise they are equivalent. And the bokeh is something to behold.