Auto Rikenon 28mm f/2.8 (incl. EE)

The Auto Rikenon 28mm f/2.8 is the moderate wide-angle of Ricoh’s M42 screw-mount system, and it came in two forms: a plain automatic-diaphragm lens for any Praktica-thread body, and an Auto Rikenon EE version made to give automatic exposure on the Auto TLS EE. Ricoh’s own accessory tables, in the SLX 500 and Auto TLS EE manuals, give both the same optical specification: 7 elements in 6 groups, focus to 0.3 m, a 58 mm filter. They differ only in the EE setting on the aperture ring and in Ricoh’s figures for weight and coverage, 240 g and 75° for the plain lens against 210 g and 74° for the EE. Dr. Ricoh’s Rikenon list repeats those figures and gives the plain lens a smallest stop of f/16. None of these sources says whether the glass inside the two is the same, who made it, or when either version was introduced or withdrawn.

The EE lens only makes sense with the camera it was made for. Ricoh’s Auto TLS EE is an M42 body with what Ricoh calls an arranged version of the Praktica mount, a mount of its own that still takes ordinary M42 lenses: with an EE lens set to EE and the lens’s maximum aperture dialled in on the body, the camera chooses the aperture for the shutter speed you set, which is shutter-priority automatic exposure. Ricoh’s accessory table lists four EE lenses for it, the 28mm, 35mm and 135mm f/2.8 and the 200mm f/3.5; camera-wiki names an EE 50mm f/1.7 as the standard lens. Ricoh calls the Auto TLS EE the first AE camera on the M42 mount; that is not right as history, since Asahi’s Pentax ES, announced in 1971 according to camera-wiki, was an aperture-priority AE camera on the same 42 mm thread before it, and the narrower claim of first shutter-priority M42 AE body is not something any source here establishes. Ricoh dates the camera to 1976; camera-wiki cites a US advertisement in Popular Photography of July 1973. On the Auto TLS EE, a non-EE lens, this plain 28mm included, is metered at full aperture by reading the stop off the viewfinder needle and setting it by hand, or metered stop-down.

On the other Ricoh M42 bodies, the Singlex TLS, Ricohflex TLS 401, SLX 500 and Singlex II, both versions are simply 28mm automatic-diaphragm screw lenses, used on their numbered stops and metered however that body meters; the EE setting does nothing there. The same goes for any other M42 body. The plain lens is a period lens for the Singlex TLS, and the TLS 401, whose instruction books list a 28mm f/2.8 among their accessory lenses; the books are undated printings, so they do not show that the lens was there at the Singlex TLS’s launch in 1967. Ricoh moved to the Pentax K bayonet with the XR-1 and XR-2 in 1977, and its later 28mm f/2.8 lenses, the XR Rikenon and Rikenon P, are separate K-mount designs with a 52 mm filter and a different construction in Dr. Ricoh’s list; they do not fit an M42 body.

For a buyer the first check is which version is in hand: an EE position on the aperture ring marks the EE lens, which matters only to someone who wants the automation on an Auto TLS EE. Then check the automatic diaphragm, since a sticky or oily aperture that does not snap closed on release will spoil exposures on any auto body, and on an Auto TLS EE check that the camera actually drives the aperture in EE mode. The 58 mm filter, against 52 mm for the K-mount XR Rikenon and Rikenon P 28mm f/2.8 in Dr. Ricoh’s list, is a quick way to tell the M42 lens from the later ones in photographs. No Ricoh or Sears catalogue or manual lists a Sears-badged 28mm as a Ricoh lens, so Sears 28mm lenses are not treated as versions of this one. No review written about either M42 version, no period price and no reproducible photograph of the lens were found.