Auto Rikenon 21mm f/3.8
Ricoh · M42 · 1967 · Nine elements in eight groups
Also known as: Auto Rikenon 21mm f3.8 · Auto Rikenon 21mm f/3.8 · Ricoh Auto Rikenon 21mm f3.8 · Ricoh Rikenon 21mm f3.8 · Rikenon 21mm f3.8 · Rikenon 21mm 1:3.8 · Auto Rikenon 1:3.8 f=21mm · Rikenon 3.8/21 · Rikenon 3,8/21 · Rikenon 21 mm f/3.8 · オートリケノン 21mm F3.8 · Rikenon 1:3.8 21mm · Rikenon 1:3.8 f=21mm
Variants & identification
| Variant | Mount | Years | Serial ranges | Production |
|---|---|---|---|---|
| Auto Rikenon 21mm f/3.8 (M42) | M42 | — | — | — |
- No launch or end date is known. The 1967 in the header is the launch year of the Singlex TLS (June 1967, per Ricoh), the first body whose instruction book lists the lens. That printing of the book is undated and already lists the 70-230mm zoom, so it may be later than 1967, and the lens may be too. The lens is also in the books of the TLS 401 (October 1970, per Ricoh), the SLX 500 (1975) and the Auto TLS EE (1976 per Ricoh; camera-wiki cites a July 1973 US magazine advertisement for it). Camera-wiki says "a selection of eighteen lenses from 21mm to 800mm" was available for the TLS 401. Dr. Ricoh gives no dates for the M42 lenses.
- Who made it is not documented: neither Ricoh's books nor Dr. Ricoh name a maker.
How to tell them apart
- Check that a listing's 21mm is f/3.8 and M42: Ricoh's later 21mm lenses are the GR 21mm f/3.5 in Leica thread and the lens fixed in the GR21 compact, neither of them this one
Auto Rikenon 21mm f/3.8 (M42):
- Maximum aperture f/3.8, not f/3.5: Ricoh's two lens tables give f/3.8 and nothing else for a Ricoh 21mm in M42
- 72 mm filter thread on a lens of only 290 g, the same filter as Ricoh's 17mm f/4 and much larger than the 62 mm of the 24mm f/2.8
- Auto (automatic diaphragm) lens with the M42 stop-down pin, listed by Ricoh under AUTO RIKENON LENSES and not among the AUTO RIKENON EE lenses, so it has no EE setting
- Auto Rikenon 21mm f/3.8 (M42): The only version documented. The Singlex TLS and TLS 401 instruction books list it as a 21mm f3.8 automatic lens. Ricoh's tables in the SLX 500 and Auto TLS EE books give the same figures: 90° angle of view, 8 groups of 9 elements, 0.3 m closest focus, 72 mm filter, 290 g (0.64 lb). Dr. Ricoh's lens table repeats them and adds f/16 as the smallest aperture, marking the entry confirmed. No Sears-badged 21mm is documented.
Specifications
- Formula
- Nine elements in eight groups
- Construction
- 9 elements / 8 groups
- Aperture range
- f/3.8–f/16
- Min. focus
- 0.3 m
- Weight
- 290 g
- Filter
- 72 mm
What reviewers say
No reviews aggregated yet — this family is still in the research queue. Written one? We'd love to index it.
History
The Auto Rikenon 21mm f/3.8 was the widest rectilinear lens in Ricoh’s screw-mount range after the 17mm f/4. It has nine elements in eight groups, covers 90° and focuses to 0.3 m. Its 72 mm filter thread is large for a lens of 290 g. It appears at the head of the accessory-lens lists in the Singlex TLS and TLS 401 instruction books, and Ricoh printed its full figures in the lens tables of the SLX 500 and Auto TLS EE books. Dr. Ricoh’s lens table agrees with them and gives f/16 as the smallest aperture. No source dates its introduction or withdrawal, and nothing says who made it for Ricoh.
It is an automatic-diaphragm lens with the standard M42 pin, and it fits the Singlex TLS, TLS 401, SLX 500 and Singlex II as any M42 lens does. On the Auto TLS EE it is not one of the EE lenses: Ricoh’s table lists those separately (28, 35, 135 and 200mm only). Ricoh’s own page for the camera says shutter-priority automation needs those dedicated lenses and that ordinary M42 lenses work with manual coupling. With the 21mm the camera’s needle shows an aperture, which the photographer then sets on the lens ring by hand; camera-wiki adds that the camera can also meter stopped down.
Only one version is documented, with no Sears-badged twin and no later revision. The lens is a sibling of the Auto Rikenon 17mm f/4, 24mm f/2.8 and 28mm f/2.8, and shares the 17mm’s 72 mm filter. When buying, confirm the engraving: a listing that says “Rikenon 21mm” with f/3.5 or Leica thread is a different lens. Ricoh’s GR 21mm f/3.5 in Leica thread and the GR21 compact, which Dr. Ricoh says share the same optics, are much later products of the GR line. The XR Rikenon and Rikenon P lenses that followed from 1977 use the Pentax K bayonet, and Dr. Ricoh’s tables of them contain no 21mm. As with any M42 wide-angle, check that the stop-down pin springs back and the diaphragm snaps open and closed cleanly, and look for haze in a front element of this size.
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 wanted — shot with a Auto Rikenon 21mm f/3.8? We'd love to feature it (with credit).
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