Auto Rikenon 50mm f/2.8 (M42)

The Auto Rikenon 50mm f/2.8 was the cheapest standard lens Ricoh offered with its last 42 mm screw-mount reflexes. Ricoh’s instruction book for the export Singlex II of August 1976 lists four standard lenses: the 55mm f/1.4, the 50mm f/1.7, the 50mm f/2 and this f/2.8. The first three have six elements in five groups; this one has four elements in three groups and takes a 52 mm filter. A later Ricoh product catalogue, from the time of the K-mount XR500, lists it again with the Singlex II and as one of the two standard lenses of the SLX 500, the other being the f/2. Ricoh dates the SLX 500 to 1975, so the lens may go back a year earlier than the Singlex II. No source shows that, and no source gives a closing date, a list price, a closest-focus distance, a blade count or a weight. Dr. Ricoh’s list carries it as its own row, separate from the 55mm f/2.8, with the 52 mm filter and nothing more.

It matters to a collector mainly because it is easily confused with two other Ricohs. The Auto Rikenon 55mm f/2.8, which Robert Allen Kautz calls the budget lens of the Singlex TLS and camera-wiki lists among the TLS 401’s standard lenses, is also a four-element, three-group lens with a 52 mm filter. Ricoh’s two documents give the 50 mm focal length, and Dr. Ricoh lists the two lenses apart and photographs a front ring engraved f=50mm, but no source sets the two side by side. Whether the 50 mm is a new design or the 55 mm under a new focal length is not known. The XR Rikenon 50mm f/2.8, which the same Ricoh catalogue lists as a standard lens of the K-mount XR500, has a bayonet. Ricoh had made a four-element 50mm f/2.8 before, as the fixed lens of the 35 Flex of 1964, but that one sits in front of a leaf shutter and does not come off, and no source links it to this lens. A listing title may leave out the XR or give the wrong focal length, so read the front ring and look at the mount before buying.

The lens fits every M42 body. On the Singlex TLS, TLS 401, Singlex II and SLX 500 it works as an ordinary automatic-diaphragm screw lens. On the Auto TLS EE it meters either at full aperture, with the needle’s reading set on the aperture ring by hand, or stopped down, as the instruction book describes for non-EE Rikenons; the camera’s shutter-priority automation needs an Auto Rikenon EE lens, and this is not one: the same book lists the 28, 35, 135 and 200 mm as the accessory EE lenses and no 50mm f/2.8 among its accessory lenses. This page links the lens to all five bodies on that basis. It is not documented as a kit lens of the Singlex TLS, TLS 401 or Auto TLS EE.

When buying, check how the aperture is switched between automatic and manual. The 55mm f/2.8 has a two-way aperture ring with AUTO and MANUAL scales instead of the slide switch on the faster Auto Rikenons, and no source says which arrangement this lens has. Press the pin and check that the blades close cleanly at every stop and spring back open. Look for oil on the blades and haze in the glass. Dr. Ricoh puts its value at €10, a collector’s estimate rather than a recorded sale.