Super-Angulon-R 21mm f4, 3-cam. Serial number in the 3,080,000 range, manufactured in 1980. Leitz catalog number 11813.
Introduced in 1968 for the Leicaflex SL. While the maximum aperture was reduced compared to its f3.4 predecessor, the rear element protrusion was made smaller, eliminating the need for mirror lock-up. Initially produced as a 2-cam lens, it was changed to 3-cam from 1977 onward. It remained in production until 1992, making it a long-selling lens.
This was Leica’s first retrofocus lens, manufactured by Schneider on an OEM basis. The optical construction consists of 8 groups and 10 elements. With multiple elements used for correction, it offers minimal distortion, high resolution, and reduced vignetting, making it an outstanding performer.

The minimum focusing distance is 0.2 m. Distance scale is in both feet and meters. Filters are either Series 8.5, inserted into the hood, or 72 mm screw-in filters.

There are slight scuffs on the front end of the barrel from attaching and removing the hood, but overall there is little sign of use and the exterior is very clean. The helicoid movement is slightly firm but does not affect practical use (servicing is available for an additional fee). The aperture ring operates smoothly. The glass shows very minor coating deterioration that can only be seen when held under LED light and should have virtually no effect on actual photography. There are no noticeable wipe marks, and the glass is clear and free from haze. Comes with the dedicated 12506 hood, front and rear caps, warranty card, and original box, making this a very clean set ideal for collection.