Nikkor 45mm f/2.8 GN non-AI (classic non-AI '68-'73, multicoated non-AI '73-'77)
This sample circa '71.
Filter size: 52mm
Close focus: 3 feet/0.8 meters
Aperture range: f/2.8 - f/32
Aperture blades: 7 (some early samples have 9)
No depth of field scale!
Design: 4 elements in 3 groups (Tessar)
Comments: This is a weird lens for many reasons. I don't use flash much, so I leave the linkage between the focus distance and the aperture off. It focuses backwards compares to other Nikkors, and the `pacing' is backwards too (a lot of rotation from infinity to 10 feet and very little from 10 feet to 3 feet, because that whole inverse square law thing). It also is missing a lot of the standard features of a lens from this era - no depth of field or IR info. It is however cute and tiny and a good performer, but the close focus is lacking, and it is expensive for the modest specifications.
Some early Nippon Kogaku versions have 9 aperture blades. The later Nippon Kogaku versions have 7 aperture blades. Nikon-marked non-multicoated samples are fairly rare, around 6400 made. The C version just adds multicoating.