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

Mamiya-Sekor Z 50mm f/4.5 W (RZ67)

Mamiya · Mamiya RZ67 · 1982

single source, unconfirmed

Also known as: Mamiya 50mm f/4.5 RZ67 · Mamiya RZ67 50mm f4.5 · Mamiya-Sekor Z 50mm f/4.5 W · Mamiya Sekor Z 50mm f/4.5 · Sekor Z 50mm W · Mamiya ULD M 50mm f/4.5 L · Mamiya 50mm ULD · Mamiya RZ 50mm 4.5 · セコールZ 50mm F4.5 · セコールZ 50mm F4.5 W · マミヤ RZ67 50mm · マミヤ ULD M 50mm F4.5 L

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor Z 50mm f/4.5 (1982 original) · Seiko #1 electronic leaf shutter, 8s–1/400, B and T; mechanical 1/400 without a battery Mamiya RZ67 1982 — —
Mamiya-Sekor Z 50mm f/4.5 W (half-stop aperture ring) · Seiko #1 electronic leaf shutter, 8s–1/400, B and T; mechanical 1/400 without a battery Mamiya RZ67 — — —
Mamiya ULD M 50mm f/4.5 L (floating group, ULD glass) · 15 elements in 11 groups with ultra-low dispersion and anomalous-dispersion glass and a floating-element system (Pro IID brochure) · Seiko #1 electronic leaf shutter, 8s–1/400, B and T; mechanical 1/400 without a battery Mamiya RZ67 — — —
  1. Z figures (9 groups/11 elements, 84°, f/32, 28 cm, 77 mm, slip-on hood) are from the RZ67 Professional instruction book at butkus.org; Z W and ULD figures including weights and dimensions are from the RZ67 Pro IID brochure (Mamiya, 2004). The Z's 760 g is the brochure's figure for the Z W, carried across because the element count is unchanged.
  2. Japanese Wikipedia gives 9群11枚 and 0.3 m for the ULD against the brochure's 15 elements in 11 groups and 0.29 m; the maker's figures are used and the difference is noted here rather than resolved.
  3. No source consulted dates the W ring or the ULD lens. The 1982 start is the instruction book of the RZ67 Professional, which lists the 50mm f/4.5; the ULD appears in the Pro IID literature of 2004.
How to tell them apart (expand)
  • Name ring sorts the three: MAMIYA-SEKOR Z 50mm f/4.5 is the original, the same with W the half-stop ring, and MAMIYA ULD M 50mm f/4.5 L the floating-element lens
  • Only the ULD has a floating-element ring to set; the Z and Z W have no ring of their own beyond the aperture and shutter-speed rings, focusing being on the body's bellows
  • Weight sorts them too: 760 g against 954 g (Pro IID brochure)
  • All three take 77 mm filters and the rectangular slip-on hood shared with the 65mm

Mamiya-Sekor Z 50mm f/4.5 (1982 original):

  • Engraved MAMIYA-SEKOR Z with no W after the aperture; aperture ring marked in whole stops (the W series added half-stop markings, Japanese Wikipedia)
  • RZ67 Professional instruction book: 9 groups, 11 elements, 84°, minimum aperture f/32, closest focus 28 cm, 77 mm filter, slip-on hood
  • Twelve electrical contacts on the rear mount that feed the body's shutter electronics; the shutter fires only through the body (RZ67 manual)

Mamiya-Sekor Z 50mm f/4.5 W (half-stop aperture ring):

  • W after the aperture on the name ring; aperture scale spaced wider with half-stop clicks (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; Emulsive: 'W denotes lenses with a wide aperture ring that has additional 1/2 stop markings')
  • Pro IID brochure: 11 elements in 9 groups, 84°, f/32, 0.28 m, 0.9× at closest, 62 × 77 mm area covered, 77 mm filter, slip-on hood, 82.2 mm long × 97.2 mm diameter, 760 g

Mamiya ULD M 50mm f/4.5 L (floating group, ULD glass):

  • ULD on the barrel and the Mamiya M name in place of Mamiya-Sekor (Japanese Wikipedia: the Sekor name was dropped on the M series); the RZ67 Wikipedia article says the ULD version 'is clearly marked'
  • A second, floating-element ring on the lens that is set to the distance read from the body's focusing scale (Emulsive's 'triple focus' procedure)
  • Pro IID brochure: 15 elements in 11 groups, 82°, f/32, 0.29 m, 0.88× at closest, 63 × 78 mm area covered, 77 mm filter, slip-on hood, 92.7 mm long × 97.2 mm diameter, 954 g

Serial-range notes

two-letter sticker on the rear of the lens
Mamiya dated RB and RZ lenses with a two-letter code stuck to the back of the lens: the first letter is the year, the second the month, A = January. Year letters run A–J for 1971–1980, A–T for 1981–2000 and A–N for 2001–2014, so the decade has to be read from the generation (Mamiya Repair). No serial-to-year table for the 50 has been published.

Specifications

Formula
Retrofocus wide-angle, 11 elements in 9 groups (Z and Z W); 15 elements in 11 groups with a floating group and ULD glass (ULD M 50mm f/4.5 L)
Construction
11 elements / 9 groups
Aperture range
f/4.5–f/32
Shutter
Seiko #1 electronic leaf shutter in the lens, 8s–1/400 plus B and T, flash sync at every speed, controlled and powered by the body's 6 V battery; without a battery the body fires the lens at a fixed mechanical 1/400 only (RZ67 manual)
Min. focus
0.28 m
Dimensions
97.2 × 82.2 mm
Weight
760 g
Filter
77 mm
Years manufactured
1982
Country
Japan
Coating
Multicoated (Mamiya's Pro IID brochure speaks of its own 'coating technologies'; no per-lens coating name is published)

What reviewers say

Optical formula — Retrofocus wide-angle, 11 elements in 9 groups (Z and Z W); 15 elements in 11 groups with a floating group and ULD glass (ULD M 50mm f/4.5 L)

No cross-section found: the RZ67 Professional and Pro IID instruction books and the Pro IID brochure at butkus.org and mamiya.org give tables of construction, angle and weight without optical diagrams, and no Mamiya data sheet for the 50 is online.

History

The 50mm f/4.5 is the RZ67’s super-wide, the equivalent of 24 mm on 35 mm by Mamiya’s own reckoning, and it was in the line from the start. The RZ67 Professional instruction book of 1982 lists it with 9 groups and 11 elements, an 84° field, f/4.5 to f/32, closest focus 28 cm on the body’s bellows, a 77 mm filter thread and the rectangular 80 mm slip-on hood it shares with the 65mm. Like every RZ lens it carries a Seiko #1 electronic leaf shutter, 8 seconds to 1/400 with B and T, timed and powered by the body’s 6 V battery; with no battery the body fires the lens at a fixed mechanical 1/400 and nothing else, which is the first thing to know when buying. The Pro IID manual adds a caution that applies to the whole family: below 1 m, use “as small an aperture as possible” on the 50 and 65 for sharp corners.

Three versions wore the name and two of them are the same glass. The original Mamiya-Sekor Z 50mm f/4.5 became the Z 50mm f/4.5 W when Mamiya widened the aperture scale and added half-stop clicks; Japanese Wikipedia describes the W series in exactly those terms, and every source consulted keeps the 11-in-9 count, so the W is a barrel change rather than a recomputation. The Pro IID brochure gives the W at 760 g, 82.2 mm long and 97.2 mm across, 0.9× at closest focus. No source consulted says when the W ring arrived.

The third is the ULD M 50mm f/4.5 L, the lens the brochure describes as employing “ultra-low dispersion and anomalous dispersion glass to achieve an extremely small amount of chromatic aberration”, with a floating-element system for “clear and uniform images … edge-to-edge”. It is a new design: 15 elements in 11 groups, 82°, 0.29 m, 954 g, and a second ring on the barrel that has to be set to the distance read off the body’s focusing scale, then the focus touched up again, the routine Pierre-gilles Lucain calls triple focus. It carries the Mamiya M name rather than Mamiya-Sekor, the mark of the later series, and the brochure prints it both as ULD M50mm f/4.5L and as M50mm ULD f/4.5L-A. Japanese Wikipedia’s nine groups and 0.3 m for the ULD do not match the brochure and are set aside. It is absent from the 1982 book and present in the 2004 literature; nothing consulted dates it more closely.

Reviewers agree on the ordering and disagree only on whether the difference matters. Lucain, who owns the W, calls it perfect for him and “awesome”, while stating that the ULD is “known to be one of the best ever made by Mamiya” and cost “more than twice the price”. Dmitri at analog.cafe reviews the body with the 110 and speaks of the lenses collectively, highly regarded for sharpness and build, and gives the buying checklist: shutter operation, smooth focus, electronic issues. Photographs on Commons from an RZ67 with the RZ 50 at f/22 show the lens as it is mostly used, stopped well down for landscape.

What to check: fit the lens to a working body with a fresh 4LR44 and run every speed, since the shutter cannot be tested off the camera; confirm the twelve rear contacts are clean and the lens cocks with the body’s lever; on a ULD, that the floating ring turns through its range and the distance marks agree with the body’s scale. RB lenses fit an RZ with 7 mm of bellows extension and the speeds set on the lens at the RBL position, but an RZ lens will not work on an RB, which has no electronics to fire it. Open questions: the date of the W ring, the date of the ULD, a list price in any currency, and the coating name, none of which any source consulted supplies.

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 taken with the Mamiya-Sekor Z 50mm f/4.5 W (RZ67)
Mata Atlântica on Fujichrome Velvia 50, Mamiya RZ67 with the RZ 50mm at f/22 (Edo Miura) — Edo Miura, via Wikimedia Commons (CC BY-SA 4.0)

Sample photo wanted — shot with a Mamiya-Sekor Z 50mm f/4.5 W (RZ67)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $300 across 43 fixed-price listings on 2026-09-19 (middle half $250–$330). First day tracked.

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

Show 86 more listings

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 2026-09-19. Links go to the shop or marketplace that carries the item.

Related: Mamiya-Sekor Z 110mm f/2.8 W (RZ67) · Mamiya-Sekor Z 180mm f/4.5 W-N (RZ67) · Mamiya-Sekor Z 250mm f/4.5 W / APO (RZ67) · Mamiya-Sekor Z 65mm f/4 W (RZ67) · Mamiya-Sekor Z 90mm f/3.5 W (RZ67)

Sources (9)

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.