This is one of a series of industrial lenses made by Nikon and introduced in 1967. It is a symmetrical design of 12 elements in eight groups. The lens was designed for ultra sharp 1:1 reproductions on 35mm film. What makes it unique is its maximum aperture of f1.0. I am using it at less than 1:1, which gives slight vignetting on full frame, but allows for a little more in the frame. Already at f1.0 the lens is very sharp, and stopping down to f1.4 increases saturation and reduces the slight halation present. Quite a piece of lens design!
