NIKON NIKKOR-O 2.1 cm f4

NIKON NIKKOR-O 2.1 cm f4 lens works with the F2 and others with mirror locked up. Hence the viewer. Viewer base damaged and repaired. Lens cover damaged.

The most obvious characteristic of this lens, as can be seen from the photograph, is that it projects a long way back from the mount. This leaves a gap of only 7mm between the lens and the film plane.

For this reason, it could only be used on a manual-focus SLR with a function for locking up the mirror, in practice the Nikon F, F2 series, etc.

For framing, the dedicated viewfinder fits in the accessory shoe of the F or F2, and focusing is carried out manually with distance scale.