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

Mamiya-Sekor Zoom C 100-200mm f/5.2 W (RB67)

Mamiya · Mamiya RB67 · 1990

single source, unconfirmed

Also known as: Mamiya 100-200mm f/5.2 RB67 · Mamiya RB67 100-200mm zoom · Mamiya-Sekor Zoom C 100-200mm f/5.2 W · Mamiya Sekor C 100-200mm f5.2 W · Mamiya 100-200 5.2 C W RB · Mamiya Sekor Zoom C 100-200 · セコールズームC 100-200mm F5.2 · マミヤ RB67 100-200mm ズーム · マミヤ セコール C 100-200mm F5.2 W

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor Zoom C 100-200mm f/5.2 W (the only version) · Seiko #1 mechanical leaf shutter, 1s–1/400 and T Mamiya RB67 1990 — —
  1. Optical and physical figures are from Mamiya's own Pro SD lens page (the Mamiya Leaf legacy site, saved as a PDF at ianbfoto.com), with Japanese Wikipedia agreeing on the construction and the two closest distances. The RB67 Camera Guide gives the same 14/12, 77 mm, 1,660 g and f/45 but a closest focus of 225 to 894 mm, which is not reconciled with Mamiya's 548 to 1,217 mm; the RZ brochure notes that its zoom's close-focus figures are with the helicoid at infinity and the bellows fully extended, which may be the difference. The table uses Mamiya's wide-end figure.
  2. The 1990 date is not the lens's introduction: it is the year of the RB67 Pro-SD, whose manual is the earliest dated Mamiya document consulted that lists the zoom, and the lens is a Sekor C, so it predates the Pro-SD. The later printing of the Pro-S instruction book at butkus.org also mentions a zoom lens without dating it. No source consulted gives the year the RB zoom appeared, a last year, or a Mamiya list price.
  3. No review on the listed sites covers the RB zoom; the Emulsive guide quoted is about the RZ67's Z 100-200mm f/5.2 W, the same 14-element, 12-group design at 1,620 g by the Emulsive table.
How to tell them apart (expand)
  • One version only, Sekor C on the barrel: the RB lens with a focusing helicoid as well as the body's bellows, and a tripod support bracket supplied
  • 166 mm long, 108.5 mm across and 1,660 g, with a 77 mm filter thread and a slip-on hood rather than the screw-in hood of the primes
  • The RZ67's Z 100-200mm f/5.2 W is the same design in the RZ bayonet with electrical contacts; an RB zoom has the RB breech-lock mount and a mechanical shutter, and needs a lens mounting ring on a Pro-SD or an RZ
  • Mamiya's G-3 front hood and sun shield are not usable on it; the G-3 bellows hood needs the zoom lens mounting ring

Mamiya-Sekor Zoom C 100-200mm f/5.2 W (the only version):

  • The only RB lens with a focusing ring: Mamiya's Pro SD lens page says it 'offers a choice of helicoid or camera bellows focusing', and the RZ brochure for its Z twin says to use the helicoid from 3 m to infinity and the bellows inside 3 m with the helicoid at infinity
  • Mamiya's Pro SD lens page: 14 elements/12 groups, 47° to 26°, automatic diaphragm, minimum aperture f/45, closest focus 548 mm at 100 mm and 1,217 mm at 200 mm, 0.45× to 0.24×, 77 mm filter, slip-on hood, 166 × 108.5 mm, 3 lb 11 oz (1,660 g); 'A tripod support bracket is included'
  • Japanese Wikipedia: セコールズームC 100〜200mmF5.2W, 12群14枚, 0.548 m at the wide end and 1.217 m at the tele end, φ77 mm
  • No K/L version is listed by the Pro-SD manual, the RB67 Camera Guide, Japanese Wikipedia or camera-wiki; the barrel reads Sekor C throughout the lens's life

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 context (Mamiya Repair). No serial-to-year table for the zoom has been published.

Specifications

Formula
14 elements in 12 groups (Mamiya Pro SD lens page, Japanese Wikipedia, camera-wiki)
Construction
14 elements / 12 groups
Aperture range
f/5.2–f/45
Shutter
Seiko #1 mechanical leaf shutter, 1s–1/400 and T, X sync at all speeds (Mamiya Pro SD lens page). Focusing is by the lens's own helicoid or by the body's bellows, the one RB lens with a choice.
Min. focus
0.548 m
Dimensions
108.5 × 166 mm
Weight
1660 g
Filter
77 mm
Years manufactured
1990
Country
Japan
Coating
Multicoated, as a Sekor C (camera-wiki); Mamiya's Pro SD lens page describes its 'proprietary multi-coating process' for the whole line

What reviewers say

Optical formula — 14 elements in 12 groups (Mamiya Pro SD lens page, Japanese Wikipedia, camera-wiki)

No cross-section found: Mamiya's Pro SD lens page gives a specification block and a product photograph, the Pro-SD manual lists only the hood, and no Mamiya data sheet for the RB zoom is online; the APO lens booklet at butkus.org, which does show cross-sections, does not cover it.

History

The 100-200mm f/5.2 W is the only zoom Mamiya made for the RB67 and the only RB lens with a focusing ring. Every other lens in the system focuses on the body’s bellows alone; Mamiya’s Pro SD lens page says the zoom “offers a choice of helicoid or camera bellows focusing”, and the RZ67 Pro IID brochure, describing the Z twin, spells out the drill: use the helicoid from 3 m to infinity, and inside 3 m set the helicoid to infinity and rack the bellows. The design is 14 elements in 12 groups, the angle of view runs from 47° to 26°, the automatic diaphragm closes to f/45, the filter thread is 77 mm and the hood is a slip-on type rather than the primes’ screw-in. At 166 mm long, 108.5 mm across and 1,660 g it is a studio lens, which is how the Pro SD page sells it: one lens “for full length portraits to head shots eliminating the need to change lenses, synch cords or camera position, throughout a sitting”, with image performance “equal to prime focal length lenses” thanks to computer-aided design and a 48 to 97 mm equivalent in 35 mm terms. A tripod support bracket is included.

Closest focus by Mamiya is 548 mm at the wide end and 1,217 mm at the tele end, at 0.45× and 0.24×, figures Japanese Wikipedia repeats; the RB67 Camera Guide’s 225 to 894 mm is a different measurement, perhaps with the bellows fully extended as the RZ brochure specifies for its own close-focus data, and the two are not reconciled here. The Seiko #1 leaf shutter runs 1 second to 1/400 with sync at every speed. The RZ brochure calls the Z version “the first zoom lens for a 6×7-format camera”.

There is one version. The barrel reads Sekor C, it is multicoated like the other C lenses, and no K/L zoom appears in the Pro-SD manual, the Camera Guide, Japanese Wikipedia or camera-wiki; the Pro-SD manual lists a hood for the zoom and Mamiya’s accessory page a zoom lens mounting ring for the G-3 bellows hood, an anti-rotation stopper that screws to the front and rails onto the zoom’s bracket so the hood does not turn with the helicoid, while the G-3 front hood and the sun shield are not usable on it. The RZ67’s Z 100-200mm f/5.2 W is the same 14-in-12 design in the RZ’s electrical bayonet; the RB lens has the breech-lock mount and a mechanical shutter, and as a Sekor C it goes on a Pro-SD or an RZ with a separate lens mounting ring, which Reznitsky’s chart recommends and the RZ brochure pairs with a service inspection. When the lens appeared is the open question: it predates the Pro-SD of 1990 because it is a C lens, and a later printing of the Pro-S instruction book already mentions a zoom, but no source consulted gives the year.

No review on the sites consulted covers the RB zoom itself. Pierre-gilles Lucain’s Emulsive guide to the RZ67 owns the Z version as his only zoom and values it for the focusing ring, noting the lens holder Mamiya made for it; Scott McClarin at Emulsive calls the Sekor C lenses exceptionally sharp and Mark Foster at Japan Camera Hunter trusts every RB lens to be sharp. What to check when buying: every shutter speed, the slow ones especially, the cocking action on and off the body, the diaphragm blades, that the zoom and focus rings turn smoothly and the helicoid reaches infinity, that the support bracket is with the lens, and dust inside the long barrel, which dealers’ listings mention. Open questions: the year of introduction, the last year, and any list price in yen or dollars, none having been found.

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 Zoom C 100-200mm f/5.2 W (RB67)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $100 across 6 fixed-price listings on 2026-09-21 (middle half $80–$120). 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 127mm f/3.8 (RB67) · Mamiya-Sekor 180mm f/4.5 (RB67) · Mamiya-Sekor 90mm f/3.8 (RB67) · Mamiya K/L 210mm f/4.5 APO L (RB67)

Sources (13)

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.