Auto Rikenon 55mm f/2.8 (M42)

Ricoh · M42 · 1967

Also known as: Auto Rikenon 55mm f2.8 · Auto Rikenon 55mm f/2.8 · Auto Rikenon 1:2.8 f=55mm · Auto Rikenon 2.8/55 · Ricoh Auto Rikenon 55mm f/2.8 · Ricoh 55mm f2.8 Auto Rikenon · Ricoh Rikenon 55mm f2.8 · Rikenon 55mm f2.8 · Rikenon 55mm f/2.8 · Rikenon 55mm 1:2.8 · Rikenon 1:2.8 55mm · Rikenon 55 mm f/2.8 · Rikenon 55 mm f2,8 · Rikenon 2,8/55 · Rikenon 55/2.8 · Rikenon 55mm 1:2,8 · オートリケノン 55mm F2.8 · リケノン 55mm F2.8 · Rikenon 1:2.8 f=55mm · Rikenon 2.8/55

Variants & identification

Variant	Mount	Years	Serial ranges	Production
Auto Rikenon 55mm f/2.8, black (M42)	M42	—	—	—

Three groups and four elements are from Dr. Ricoh's Rikenon list (entry R10203165, 2.8/55 M42), the only source to give a formula for the 55 mm lens. Ricoh's own Singlex II instruction book gives exactly that formula, 3 groups and 4 elements, for a 50 mm Auto Rikenon f/2.8, and camera-wiki copies it. Dr. Ricoh lists a separate 2.8/50 M42 Auto with a 52 mm filter and no further data. Whether the 50 mm and 55 mm f/2.8 are two lenses, or the manual and Dr. Ricoh's 50 mm row describe this one under a rounded focal length, is not settled; Ricoh's manual is the primary source, but no 50 mm f/2.8 example has been checked against this lens here.
Smallest aperture f/22 from Dr. Ricoh, collection-appareils.fr and the Commons photograph, whose two scales both end at 22. Robert Allen Kautz's review gives f/2.8–f/16; no example stopping at f/16 is on record, so f/22 is kept.
Closest focus 0.9 m from Kamerastore, collection-appareils.fr and Kautz. Dr. Ricoh's table carries 100 in its distance column (1 m) for this lens.
Weight: Kamerastore gives 159 g, collection-appareils.fr 180 g. Neither is a maker figure, so no weight is set in the table.
Dates: Kautz writes that the lens was sold in 1967 as the budget option for the Singlex TLS, and that is the year this page carries. Ricoh's own instruction books back the tie to the body without dating it: the Singlex TLS book (an undated printing) lists a '55mm f 2.8 automatic' and gives separate instructions for 'the f/2.8 55mm lens with the Singlex TLS camera', with its AUTO and MANUAL scales, and an English TLS 401 book says 'The f:/2.8 55mm lens is now available with TLS 401 camera'. The year agrees with Ricoh's own date for the Singlex TLS, June 1967 (Japanese Wikipedia gives January 1964 for the camera), but Ricoh does not name the f/2.8 among that camera's kits, which it prices only with the f/1.4 (¥51,000) and the f/1.8 (¥42,000), Japanese list prices for body and lens together. Japanese Wikipedia dates its photograph only as '1960s?'. Camera-wiki lists the f/2.8 55mm among the TLS 401's standard lenses (October 1970), depending on the camera's age, but Ricoh's own TLS 401 entry prices the body only with the f/1.4 (¥57,500) and the f/1.8 (¥47,500), on the same terms. No Ricoh price list, catalogue or end date for the f/2.8 has been found.
In a 2008 MFLenses forum thread about Auto Sears lenses, an owner described a 55mm f/2.8 (not the macro) with 'two sets of aperture stops', f/2.8 in the centre, manual to the right and auto to the left, and a front cap with the Sears emblem; he did not spell out the engraving on the lens itself. No photograph or Sears catalogue entry has been found, so no Sears version is listed as a variant. The same thread lists a separate Auto Sears 55mm f/2.8 Macro sold with a matched extension ring for 1:1; that is a different lens.
Not this lens: the Rikenon 55mm f/2.8 of the Ricoh 126 C Flex (November 1969, ¥26,800 with the lens), 3 groups and 4 elements, (Ricoh), which screws into that camera's own Ricoh M29 thread and has no aperture of its own (Dr. Ricoh), and the K-mount XR Rikenon lenses of 1977 onward.

How to tell them apart (expand)

AUTO RIKENON 1:2.8 f=55mm on the front ring. The f/1.4 and f/1.8 Auto Rikenons read 1:1.4 and 1:1.8; Ricoh's K-mount lenses read XR RIKENON or RIKENON P and have a bayonet, not a 42 mm thread
The two-way aperture ring with AUTO and MANUAL scales, in place of the slide switch on the faster Auto Rikenons, is the quickest tell in a photo
Small and light for a standard lens: about 60 × 40 mm, 52 mm filter, five aperture blades

Auto Rikenon 55mm f/2.8, black (M42):

Front ring engraved MADE IN JAPAN, AUTO RIKENON 1:2.8 f=55mm and a serial number, inside a bright filter rim; black metal barrel (Wikimedia Commons photograph by Denis Barthel; Kamerastore)
No separate A/M switch: the aperture ring carries two scales that meet at f/2.8, one engraved AUTO (22 · 11 · 5.6 · 2.8) and one engraved MANUAL (2.8 · 5.6 · 11 · 22, in colour on the Commons example). Robert Allen Kautz describes the ring as two-sided, one side manual and the other auto
Focusing scale in metres (green) and feet (white); 52 mm filter thread; about 60 mm across and 40 mm long

Auto Rikenon 55mm f/2.8, black (M42): The only Ricoh-badged version known. The examples on record (the Commons photograph, Kamerastore's listings, the collection-appareils.fr example, Kautz's test lens) are all the Auto Rikenon for the 42 mm thread with the two-way aperture ring; Kamerastore and the Commons photograph show it in black metal, and no chrome version is known. Kamerastore's catalogue entry gives 0.9 m, five blades, 60 × 40 mm and 159 g; the collection-appareils.fr entry gives f/22, 0.9 m, five blades, 60 × 40 mm, 180 g, a 52 mm filter and no multicoating.

Specifications

Construction: 4 elements / 3 groups
Aperture range: f/2.8–f/22
Diaphragm blades: 5
Min. focus: 0.9 m
Dimensions: 60 × 40 mm
Filter: 52 mm
Country: Japan
Coating: Not multicoated (collection-appareils.fr); no maker statement found

What reviewers say

Robert Allen Kautz (blog) — Tested on a Canon EOS 6D: sharp in the centre from f/2.8 and razor-sharp there by f/5.6, corners average wide open and good by f/5.6, high contrast at some cost to shadow detail, almost no fringing, vignetting at f/2.8, and more barrel distortion than most standard primes. Smooth, well-damped mechanics. His verdict on whether it is any good: yes, with a three-dimensional look he likens to EBC Fujinons and Hexanons.

Optical formula

No cross-section found. Dr. Ricoh's table and Ricoh's Singlex II instruction book give only the 3-group / 4-element count, and no Ricoh lens catalogue for the M42 line is on record.

History

The Auto Rikenon 55mm f/2.8 was the cheap standard lens of Ricoh’s 42 mm screw-mount reflexes. It is a small four-element lens in three groups (Dr. Ricoh) for the 42 mm thread Ricoh took up with the Singlex TLS (June 1967 by Ricoh’s date; Japanese Wikipedia gives 1964). It sat below the Auto Rikenon 55mm f/1.4 and f/1.8. Robert Allen Kautz writes that it was sold in 1967 as the budget option for the Singlex TLS. Ricoh’s Singlex TLS instruction book gives the lens instructions of its own, and an English TLS 401 book says it was ‘now available’ with that camera; camera-wiki lists it among the standard lenses of the Ricohflex TLS 401 of 1970, depending on the camera’s age. Ricoh’s own Japanese entries for those bodies price them only with the f/1.4 or the f/1.8. No Ricoh price, catalogue page or end date for the lens has been found.

It is easy to spot. The faster Auto Rikenons have a slide switch for auto and manual. This lens has none: its aperture ring carries two scales that meet at f/2.8, one engraved AUTO and the other MANUAL. Turned one way from f/2.8, the ring sets the aperture for automatic stop-down at the release; turned the other way, it closes the diaphragm directly for stop-down metering. The front ring reads AUTO RIKENON 1:2.8 f=55mm. The lens takes 52 mm filters and has five blades. Kamerastore and a French collectors’ site agree on 0.9 m closest focus and a barrel about 60 × 40 mm, but give 159 g and 180 g for the weight. In a 2008 MFLenses forum thread on Auto Sears lenses, an owner described a 55mm f/2.8 with the same two-way ring and a Sears-emblem cap, which suggests a Sears version, but no photograph or Sears catalogue entry has turned up. The Auto Sears 55mm f/2.8 Macro sold with an extension ring is a different lens.

There is an open question about a 50 mm twin. Ricoh’s own instruction book for the export Singlex II of 1976 lists a 50 mm Auto Rikenon f/2.8 of exactly this formula, 3 groups and 4 elements, and Dr. Ricoh carries both a 2.8/55 and a 2.8/50 in his M42 table. They may be two lenses, or the same lens under a rounded focal length. Until a 50 mm f/2.8 example is set beside this one, read the engraving and buy by what it says. Two other Ricoh lenses share the 55mm f/2.8 name and are not this one. The Rikenon 55mm f/2.8 of the 126 C Flex of 1969 screws into that camera’s own M29 thread and has no diaphragm of its own. The XR Rikenon lenses of 1977 onward are Pentax K bayonet lenses.

The lens fits every M42 body. On the Singlex TLS, TLS 401, Singlex II and SLX 500 it works as any automatic-diaphragm screw lens does. On the Auto TLS EE it meters either at full aperture, with the 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 EE Auto Rikenon, and this is not one: the same book lists only the 28, 35, 135 and 200 mm among the accessory EE lenses. Kautz’s test on a full-frame digital body found it sharp in the centre from f/2.8 and very sharp by f/5.6, with only average corners wide open, high contrast, a little vignetting and more barrel distortion than most standard lenses. When buying, turn the aperture ring through both scales and check on the AUTO side that the blades close to the set aperture when the pin is pressed and spring fully open when it is released. Look for oil on the blades and haze in the glass. These sell cheaply: Kamerastore’s average price for a certified copy is €39, a dealer price with VAT treatment not stated.

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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.

Example photos

Sample photo taken with the Auto Rikenon 55mm f/2.8 (M42) — Auto Rikenon 55mm f/2.8: the front-ring engraving and the two-way aperture ring, AUTO on one side of f/2.8 and MANUAL on the other — Denis Barthel, via Wikimedia Commons (CC BY-SA 4.0)

More sample photos elsewhere

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Sample photo wanted — shot with a Auto Rikenon 55mm f/2.8 (M42)? We'd love to feature it (with credit).

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