Auto Rikenon 50mm f/1.7 (M42)

Ricoh · M42 · 1967

our own finding

Also known as: Auto Rikenon 50mm f/1.7 · Auto Rikenon 50mm f1.7 · Ricoh Auto Rikenon 50mm f/1.7 · Ricoh 50mm f1.7 Auto Rikenon · Ricoh 50mm f1.7 Auto Rikenon M42 · Auto Rikenon 1:1.7 f=50mm · Auto Rikenon 1.7/50 · Rikenon 50mm f1.7 M42 · Rikenon 1.7/50 M42 · Rikenon 50 mm f/1.7 Auto · Rikenon 1.7/50 · Rikenon 1,7/50 · Rikenon 50 mm f/1.7 · オートリケノン 50mm F1.7 · リコーオートリケノン 50mm F1.7 · Auto Rikenon 1:1.7 50mm · Auto Rikenon 50mm 1:1.7 · Rikenon 1:1.7 50mm M42 · Rikenon 1:1.7 f=50mm M42 · Rikenon 50mm 1:1.7 M42 · Rikenon 50 mm f/1.7 M42

Variants & identification

Variant	Mount	Years	Serial ranges	Production
Auto Rikenon 50mm f/1.7	M42	—	—	—
Auto Rikenon EE 50mm f/1.7	M42, with Ricoh's EE coupling for the Auto TLS EE	—	—	—

Construction is in dispute. Dr. Ricoh's table and Kamerastore's listing give four groups and six elements; camera-wiki's Singlex II page gives five groups and six elements. All three agree on six elements, so the page gives that and leaves the group count out.
Dimensions and weight disagree by source and are left out of the specification: Dr. Ricoh gives 63 mm diameter, 52 mm length and 200 g; Kamerastore 62 × 48 mm and 236 g; allphotolenses 40 mm and 235 g. Dr. Ricoh's closest-focus column reads 150 cm for this lens, against 0.5 m from Kamerastore and allphotolenses; the 0.5 m is used here.
The six-blade diaphragm and 0.5 m closest focus come from a dealer listing and a lens database, not from a Ricoh document. The 52 mm filter is Dr. Ricoh's figure and allphotolenses' too.
No source dates the lens itself. 1967 is the year Ricoh gives for the Singlex TLS, whose instruction book lists a '50mm f 1.7 automatic' among its accessory lenses; the TLS 401 book (1970 by Ricoh) lists it too. Both books are undated printings, so 1967 is the earliest year the ordinary lens can be tied to, not a launch date. The Sears T.L.S. manual, for Sears's version of the Singlex TLS, lists an outfit 'with f:1.7 lens' (3 7323) beside the f:1.8 and f:1.4 outfits, without a focal length. Camera-wiki's TLS 401 page implies the ordinary lens came in during that body's run, after its 1970 launch, and Ricoh's own TLS 401 entry prices kits with the f/1.4 and f/1.8 only. The EE version is tied to the Auto TLS EE, which Ricoh dates to 1976 and camera-wiki to a US magazine advertisement of July 1973. No end date has been found; Ricoh moved to the Pentax K bayonet in 1977.
Whether the EE lens shares the ordinary lens's optics is unknown. Dr. Ricoh's row for it is blank, and no cross-section or element count for it is on record.
No list price for either version is on record, in yen or in dollars.

How to tell them apart (expand)

Engraved RIKENON 1:1.7 f=50mm on the front ring; the EE version adds EE after RIKENON and an EE position on the aperture ring
52 mm filter thread; aperture f/1.7 to f/16
M42 screw mount with an automatic-diaphragm pin. The K-mount XR Rikenon 50mm f/1.7 of 1977 and the later Rikenon and Rikenon P 50mm f/1.7 (Dr. Ricoh's Pentax-K rows) are bayonet lenses with no thread at the rear, and belong to other pages

Auto Rikenon 50mm f/1.7:

Front ring engraved …RIKENON 1:1.7 f=50mm, then a six-digit serial and LENS… (Kamerastore's photograph of serial 020575)
Aperture ring runs 16 to 1.7 and ends there, with no EE position beside the 1.7
Black barrel with a scalloped metal focusing grip; distance scale in feet in white and metres in green, depth-of-field scale from 16 to 16 either side of a red index

Auto Rikenon EE 50mm f/1.7:

Front ring engraved AUTO RIKENON EE 1:1.7 f=50mm, serial, LENS MADE IN JAPAN, with EE picked out in green (Coastal Film Lab's photographs of serial 009868 on an Auto TLS EE)
An EE setting on the aperture ring beyond the wide-open end: Ricoh's Auto TLS EE manual calls it the EE/Manual Ring, and its close-ups (Figs. 6 and 14) show it reading 16 11 8 5.6 4 2.8 2 1.7 EE
Black barrel with a scalloped grip like the ordinary lens's (Coastal Film Lab's photographs)

Auto Rikenon 50mm f/1.7: The ordinary automatic-diaphragm M42 lens. Camera-wiki names it as one of three standard lenses for the TLS 401 ("f/1.4 55mm, f/1.7 50mm or f/2.8 55mm (dependant on the age of the camera)") and as a standard lens of the Singlex II of 1976. Ricoh's own TLS 401 entry of October 1970 lists kits with an f/1.4 and an f/1.8 lens only. The accessory-lens lists in the instruction books of the Singlex TLS and TLS 401, both undated printings, already include a '50mm f 1.7 automatic', and the Sears T.L.S. manual offers an outfit 'with f:1.7 lens' (catalogue number 3 7323) without giving its focal length. Dr. Ricoh's M42 table gives it a row of its own (4 groups, 6 elements, 52 mm filter, 200 g); Kamerastore describes a black metal example as 6 elements in 4 groups, 0.5 m, six blades, 62 × 48 mm and 236 g.
Auto Rikenon EE 50mm f/1.7: The standard lens of the Auto TLS EE. Ricoh's manual for that body tells the owner to set the EE/Manual Ring to EE and turn the Lens Selection Dial to the lens's maximum aperture, and gives this lens as the example: "if the speed of your Auto Rikenon EE lens is f/1.7, set the Dial at 1.7". The manual's own camera photograph shows a lens engraved 1:1.7 f=50mm. On the Auto TLS EE the body then sets the aperture itself, shutter priority; on any other M42 body, or with the ring off EE, it is an ordinary lens set by hand. Dr. Ricoh lists a "1.7/50 Auto EE M42" as a separate row and gives it no specifications, and no source says whether its optics are those of the ordinary lens.

Serial-range notes

009868, 020575: Two numbers seen on photographed lenses, both six digits with a leading zero: 009868 on an EE lens (Coastal Film Lab) and 020575 on an ordinary lens (Kamerastore). No serial list for Rikenon lenses is on record, so neither dates its lens, and two numbers do not show whether the EE and ordinary lenses share one sequence.

Specifications

Formula: Six elements; four groups per Dr. Ricoh and Kamerastore, five per camera-wiki
Construction: 6 elements
Aperture range: f/1.7–f/16
Diaphragm blades: 6
Min. focus: 0.5 m
Filter: 52 mm
Country: Japan

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History

The Auto Rikenon 50mm f/1.7 is a fast standard lens of Ricoh’s screw-mount reflexes, from the Singlex TLS of 1967 to the move to the Pentax K bayonet with the XR-1 and XR-2 in 1977. The accessory-lens lists in the Singlex TLS and TLS 401 instruction books, both undated printings, include a 50mm f/1.7, although Ricoh’s own entry for the TLS 401 of 1970 prices kits only with the f/1.4 and f/1.8. Camera-wiki lists it among the TLS 401’s standard lenses “dependant on the age of the camera”, and as a standard lens for the export Singlex II of 1976. It fits every M42 body Ricoh made, and any other 42 mm screw-mount camera with a pin to work its automatic diaphragm. It is an ordinary lens of its kind: six elements, a 52 mm filter, f/1.7 to f/16, and in the examples photographed, a black barrel with a scalloped metal grip.

It came in two versions, and the difference matters only on one camera. The Auto Rikenon EE 50mm f/1.7 was the standard lens of the Auto TLS EE. On that body the aperture ring is turned to its EE position, which sits past f/1.7 at the wide-open end of the scale, the camera’s Lens Selection Dial is set to 1.7, and the body then chooses the aperture for the shutter speed set, with a needle in the finder showing which one. Ricoh’s own manual uses this lens as its example. Ricoh’s camera list calls the Auto TLS EE the first AE camera on an M42 mount. That is Ricoh’s claim, and it is wrong as history: Asahi’s Pentax ES of 1971 was an aperture-priority AE screw-mount reflex, and the Fujica ST901 of 1974 also came before Ricoh’s own 1976 date. The Auto TLS EE was a shutter-priority camera; whether it was the first M42 body with shutter-priority automation has not been established. On the Singlex TLS, TLS 401, SLX 500 or Singlex II, or on any other M42 body, the EE lens should work like the ordinary one, as an automatic-diaphragm lens with the ring set to a marked aperture and the EE position unused; no Ricoh document describes that use. Whether the two versions share their optics is not known. Dr. Ricoh’s list gives the EE lens a row of its own but no specifications.

To tell them apart from photographs, look at the front ring and the aperture ring. The EE lens reads AUTO RIKENON EE 1:1.7 f=50mm, with EE in green, and has an EE setting on the aperture ring next to the 1.7. The ordinary lens has neither. Listings also mix both versions up with the K-mount XR Rikenon 50mm f/1.7 of 1977 and the later Rikenon and Rikenon P 50mm f/1.7. Those are bayonet lenses, with no thread at the rear. The sources do not agree on the lens’s construction (four groups or five), weight (200 g or about 235 g) or closest focus, and Ricoh’s own pages give no lens specifications for these bodies. Who made the glass is also unknown. The only attribution found is a 2010 forum post guessing that Tomioka made it because it looks like a Yashica lens, and the thread’s starter doubted such guesses. No period list price has been found for either version.

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This history is AI-written, from the sources listed at the foot of the page. Where the record is silent it says so rather than filling the gap — but no human wrote these sentences.

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