Glass Bodies a variant-level encyclopedia of vintage lenses and cameras by iwillpat

Mamiya-Sekor Fisheye Z 37mm f/4.5 W (RZ67)

Mamiya · Mamiya RZ67 · 1982

single source, unconfirmed

Also known as: Mamiya-Sekor Fisheye Z 37mm f/4.5 W · Mamiya Sekor Z 37mm F4.5 W Fisheye · Mamiya Sekor Fisheye Z 37mm f/4.5 · Mamiya RZ67 37mm f/4.5 Fisheye · Mamiya RZ 37mm 4.5 fisheye · Fisheye Z37mm f/4.5W · マミヤ セコール フィッシュアイ Z 37mm F4.5 W · マミヤセコールZ 37mm F4.5 魚眼 · マミヤ RZ67 37mm F4.5

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor Fisheye Z 37mm f/4.5 (1982, full-stop aperture ring) Mamiya RZ67 1982 — —
Mamiya-Sekor Fisheye Z 37mm f/4.5 W (half-stop aperture ring) Mamiya RZ67 — — —
  1. The W designation is explained by Japanese Wikipedia (絞り目盛の間隔が広くなり、1/2段絞りが追加された: wider aperture-scale spacing, half stops added) and by Emulsive (half-stop markings, optics unchanged). No Mamiya document consulted states the year the W barrel replaced the plain Z.
  2. Construction, angle of view, minimum aperture and closest focus for the 1982 lens are from the RZ67 Professional instruction manual's lens table, whose closest-focus column is measured from the film plane. The manual gives no weights.
  3. Weight, dimensions and magnification are from Mamiya's Mamiya-Sekor Z Interchangeable Lenses sheet, whose minimum-focus column is measured from the lens front rim with the bellows fully extended (46 mm), not from the film plane; the 2004 brochure prints the same 6.4 mm figure as 0.26 m from the film plane. The sheet's dimension column is read here as diameter × length, and the brochure's 100.3 × 112 mm as length × diameter.
  4. The 40.5 mm filter is a rear-mounted filter (Emulsive; the 2004 brochure lists a dedicated 40.5 mm filter set), and no front filter or hood is possible on the bulbous front element. Only Emulsive states that the lens is computed to be used with a filter in place: single source.
  5. No aperture-blade count, coating description or list price in any currency was found in a Mamiya document; those fields are left empty rather than guessed.
How to tell them apart (expand)
  • Every version: RZ bayonet with 12 electrical contacts and a Seiko #1 electronic leaf shutter; no shutter-speed ring on the lens, since the body dial sets it. A 37mm fisheye with its own speed ring is the RB67's Sekor Fisheye C 37mm f/4.5, a different lens that mounts on an RZ with the dial at RBL
  • No W on the name ring and a full-stop aperture ring means the 1982 lens; W with half-stop clicks means the later barrel
  • A bulbous, uncovered front element with a fixed scalloped shade, a 40.5 mm rear filter thread and no front thread; 112 mm across and 1280 g, the widest and one of the heaviest short lenses in the system

Mamiya-Sekor Fisheye Z 37mm f/4.5 (1982, full-stop aperture ring):

  • Engraved MAMIYA-SEKOR FISHEYE Z f=37mm 1:4.5 with no W after the aperture; aperture ring clicks at full stops only¹
  • 1982 RZ67 instruction manual: 9 elements in 6 groups, 180° angle of view, f/32 minimum, 25.7 cm closest focus, 40.5 mm filter, no hood²
  • Soft leather lens case No. 4 in the 1982 accessory list is made for this lens alone

Mamiya-Sekor Fisheye Z 37mm f/4.5 W (half-stop aperture ring):

  • W after the aperture on the name ring; aperture ring with half-stop clicks and wider scale spacing¹
  • Mamiya-Sekor Z lens sheet: 9 elements in 6 groups, 180°, f/32, 1.23× at full bellows extension (6.4 mm from the front rim), 18 mm equivalent, 40.5 mm filter, no hood, 112 × 100 mm, 1280 g³
  • 2004 Pro IID brochure: the same construction, 0.26 m closest focus, 100.3 × 112 mm, 1,280 g, lens hood 'none required'; still in the line-up as Fisheye Z37mm f/4.5W
  • Japanese Wikipedia: セコールフィッシュアイZ 37mmF4.5W, 6群9枚, 0.257 m, φ40.5 mm screw-in

Specifications

Formula
Diagonal fisheye, 9 elements in 6 groups (1982 RZ67 manual; Mamiya-Sekor Z lens sheet)
Construction
9 elements / 6 groups
Aperture range
f/4.5–f/32
Shutter
Seiko #1 electronic leaf shutter in the lens, 8s–1/400 plus B and T, set from the body dial; a mechanical 1/400 works without a battery
Min. focus
0.257 m
Dimensions
112 × 100 mm
Weight
1280 g
Filter
40.5 mm
Years manufactured
1982
Country
Japan

What reviewers say

Optical formula — Diagonal fisheye, 9 elements in 6 groups (1982 RZ67 manual; Mamiya-Sekor Z lens sheet)

History

The 37mm f/4.5 is the widest lens made for the RZ67 and the only fisheye: a full-frame diagonal fisheye that covers 180° corner to corner of the 6×7 frame, or about 18 mm in 35 mm terms by Mamiya’s own conversion. It was in the system from the start. The 1982 RZ67 Professional manual lists it first in the lens table with 9 elements in 6 groups, f/4.5 to f/32, a closest focus of 25.7 cm from the film plane and a 40.5 mm filter, and gives it a lens case of its own, the No. 4. Mamiya’s later Mamiya-Sekor Z lens sheet adds a 112 × 100 mm barrel and 1280 g, and a close-up figure that reads oddly until the column heading is understood: 6.4 mm is the subject distance from the front rim with the body’s 46 mm bellows racked out, at which point the lens covers 4.5 × 5.6 cm at 1.23×. The 2004 Pro IID brochure prints the same lens, the same figures and a closest focus of 0.26 m, so the design never changed.

Two versions exist and they differ in the aperture ring only. The 1982 lens is engraved Mamiya-Sekor Fisheye Z 37mm 1:4.5 and clicks at full stops; the W barrel that replaced it carries a W after the aperture, a wider-spaced scale and half-stop clicks. Japanese Wikipedia describes the W change in those terms and Pierre-Gilles Lucain’s Emulsive guide says the non-W lenses were made only for the first Professional body and are optically identical; he owns a non-W 37 and reports no difference. No Mamiya document consulted dates the change. The RB67 has a Sekor Fisheye C 37mm f/4.5 of the same construction that mounts on an RZ body with the dial at RBL, but it carries its own shutter-speed ring and is a different lens with its own page.

Lucain’s is the only review found. He likes wide lenses and calls the 37 fantastic, with the caveats a fisheye brings: the projection is not corrected, so straight lines bow unless they pass through the centre, and the satisfaction is in compositions that do not look like fisheye pictures. The practical points he raises are Mamiya’s own. The front element is bulbous and uncovered behind a fixed scalloped shade, so there is no front thread and no hood; filtration is by a 40.5 mm filter at the rear, for which the 2004 brochure lists UV, SL-1B, LB-A and LB-B, and Lucain says the lens is computed with a filter in place. The extension tubes and the 1.4× teleconverter are not for use with it, and the body’s bellows already puts the subject almost on the glass.

Buying advice is the RZ system’s, with the fisheye’s own additions. The Seiko #1 electronic leaf shutter fires only with a working 6 V battery in the body; without one it gives a mechanical 1/400 and nothing else. The shutter is cocked by the body’s lever with the mirror down, and the lens will not come off unless it is cocked. Run the shutter at 8 s and 1/400 and watch the blades, work the depth-of-field preview and T levers, and inspect the 12 rear contacts. On this lens, check the exposed front element under a raking light for cleaning marks and chips, since it cannot be protected, and confirm that a rear filter is present or that the 40.5 mm thread is clean, because the lens is meant to be shot with one.

What could not be sourced: the number of aperture blades, a description of the coating, a list price in yen or dollars, a weight for the 1982 non-W barrel, the year the W barrel arrived, and the year production ended. No designer is named anywhere.

Expand Collapse

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 Mamiya-Sekor Fisheye Z 37mm f/4.5 W (RZ67)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $2,000 across 3 fixed-price listings on 2026-09-21 (middle half $1,800–$2,000). First day tracked.

Asking prices from the listings scanned, not sales; junk-flagged rows and auction lots excluded; other currencies are not converted.

Buying from Yahoo! Auctions outside Japan. It is a domestic marketplace: sellers ship within Japan, and most will not register an overseas buyer. A proxy service bids on your behalf, receives the item and forwards it, for a fee and a wait. Buyee, Jauce and ZenMarket each accept a Yahoo auction number directly. Listed alphabetically for information — none is recommended over another, and none of these is an affiliate link.

Listings updated 2026-09-21. Links go to the shop or marketplace that carries the item.

Related: Mamiya-Sekor Z 50mm f/4.5 W (RZ67) · Mamiya-Sekor Z 65mm f/4 W (RZ67) · Mamiya M 75mm f/3.5 L (RZ67) · Mamiya-Sekor Shift Z 75mm f/4.5 W (RZ67)

Sources (8)

Every page here is assembled from public sources, and the gaps are real ones. If you own this lens, know a serial number I'm missing, or can see where I have it wrong, tell me — corrections, serials and sample photos are all worth having.