Leica Summicron-R II 50mm F2 lens. 3rd cam. ( 1978). Made in Canada.

Leica’s series of lenses for single lens reflex cameras are designated R-series lenses, and are generally identified by the addition of the letter-R- after the lens name.  The Leica R mount is a three lug bayonet mount with a 47mm flange focal distance. Although the R lens bayonet has remained substantially unchanged since its introduction in 1964, the R lenses can be divided into 4 general categories: one-cam lenses , being the lenses manufactured concurrently with and intended for use on the original Leica-flex body; two cam lenses , being the lenses manufactured concurrently with and intended for use on the Leica-flex SL and SL2 models, as well as the original Leica-flex three cam lenses, being the lenses manufactured concurrently with and intended to use on the Leica R3 and later models only.  3^rd-cam or R-only cam is for use on the R3 and later models. This lens has not the 1or2 cam and has only the 3e cam (black tiered cam) located between the lens mount and the rear element, these lenses also have a slightly different mount shape that prevents it from fitting on earlier camera models ( Leicaflex)

Specifications:

Lens type: Standard lens.

Angle of view: 47 °

Variations: 1-cam, 2-cam, 3-cam, black and chrome.

Optica construction: 6 lenses in 4 groups.

F-stop range : f/2—f/16 in half stops.

Closest focusing distance : 50cm

Diaphragm setting type: 6 blades.

Filter type : Series E55

Accessories : Hood. Built-in

Dimensions: 41x66mm

Weight : 290 gram