Rikenon 500mm f/8 (M42)

The Rikenon 500mm f/8 is the shortest of the three non-automatic super-telephotos in Ricoh’s lens table for its M42 screw-mount reflexes. It is known from the maker’s own accessory list rather than from surviving examples: the Auto TLS EE instruction book lists it first among the plain RIKENON LENSES, after the Auto Rikenon EE and Auto Rikenon groups, as a 500mm f8.0 of 4 elements in 4 groups, focusing to 4.0 m, covering 5°, taking a 77 mm filter and weighing 1,000 g. The 600mm and 800mm f/8 below it on the same list weigh 2.6 kg and 2.37 kg and are marked Preset. The 500mm has nothing in its F-stop Control column at all. The Singlex TLS and TLS 401 books list it the same way, as a ‘500mm f 8.0’ with neither ‘automatic’ nor ‘preset’ beside it, where the 600mm and 800mm are marked preset.

Whether it is a mirror lens is the open question. Dr. Ricoh’s Rikenon list, an independent collector’s table of the whole range, repeats Ricoh’s figures and calls it a mirror lens, giving f/8 as both its largest and smallest stop, which is how a fixed-aperture catadioptric would be listed. The same entry also says “Preset”, which a fixed-aperture lens would not need, and Ricoh itself never names the optical type. The blank aperture column and the light weight next to the two preset lenses fit Dr. Ricoh’s reading, but until a photographed example turns up, the mirror description rests on that one list. It should not be confused with the XR Rikenon Reflex 600mm f/8, a Pentax K bayonet mirror lens of the 1980s that belongs to the later XR system.

Without an automatic diaphragm, the lens works the same way on every Ricoh screw-mount body: the Singlex TLS, the Ricohflex TLS 401, the SLX 500, the Singlex II and the Auto TLS EE. The first four meter through the lens stopped down, which with this lens means at f/8. The Auto TLS EE gives its shutter-priority automation only with Auto Rikenon EE lenses. Its instruction book offers two manual methods for non-EE Rikenons and other screw-mount lenses: full-aperture measuring with the lens speed set on a dial, which it limits to lenses of f/5.6 or faster, and stopped-down measuring. An f/8 lens falls outside the first, so on that body the 500mm is metered stopped down and set by hand, as on the others. Because the thread is standard M42, it also fits Pentax, Praktica, Fujica and other screw-mount bodies.

Little is recorded about surviving examples. No dealer listing, auction result or published review of a Ricoh-branded M42 500mm f/8 is on record, and no Sears-badged version is known, although Sears sold other Rikenons under its own name. Dr. Ricoh puts its value at €60, the list’s undated estimate for an example in very good condition rather than a recorded sale, and no list price from the period is recorded. Anyone who finds one should check whether it is a mirror lens, with a central obstruction visible from the front, and whether it has any aperture ring or preset ring. A photograph of the engraving would settle more than any source used here. Beyond that, check it as you would any long telephoto: look for haze on the front elements, a bent filter thread and a dry focusing helicoid, and on a mirror design, for tarnish or loose mirrors. Its maker, its dates and the exact name engraved on it all remain unrecorded.