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

Mamiya-Sekor C 80mm f/1.9 (645)

Mamiya · Mamiya 645 · 1976

single source, unconfirmed our own finding

Also known as: Mamiya-Sekor C 80mm f/1.9 · Mamiya Sekor C 80mm f1.9 · Mamiya-Sekor C 80mm f/1.9 N · Mamiya 645 80mm f/1.9 · Mamiya 645 80mm f1.9 N · Mamiya M645 80mm 1.9 · Sekor C 1:1.9 f=80mm · マミヤ セコールC 80mm F1.9 · マミヤ645 80mm F1.9 · セコールC 80mm F1.9 N · SEKOR C 80mm F1.9 New

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor C 80mm f/1.9 (original) Mamiya 645 1976 — —
Mamiya-Sekor C 80mm f/1.9 N Mamiya 645 1985 — —
  1. Element counts, closest focus, filter size, dimensions and weight are from Mamiya's C-era lens brochure (cameramanuals.org) and the N-era 645 Interchangeable Lenses instruction sheet (Butkus library); the two agree on every figure.
  2. The family year: the lens is not among the seven Modern Photography listed for the M645 in September 1975 or January 1976, but is a standard-lens option in the M645 instruction manual and with the M645 1000S of November 1976. 1976 is therefore the earliest year it is attested here, not a documented release date.
  3. Aperture blade count (6) comes only from the Wikipedia lens table; no Mamiya document consulted gives it.
  4. The N variant's start year is the 645 Super's launch (December 1985, Japanese Wikipedia; camera-wiki); no source dates the end of C production, and Wikipedia says the Super was sold with the C lens early and the N lens late.
How to tell them apart (expand)
  • Two versions, same glass: plain C (metal aperture ring) or N after the aperture (plastic aperture ring, revised coatings); size and weight identical at 59 mm and 420 g
  • 67 mm filter thread where the 80mm f/2.8 takes 58 mm; the front is the quickest way to tell the two 80s apart at a glance
  • The C-era Sekor C instruction sheet warns that the No. 3 auto extension ring used with this lens must be the 3-S type, or vignetting results

Mamiya-Sekor C 80mm f/1.9 (original):

  • Name ring reads Sekor C with no N after the aperture; metal aperture ring (Wikipedia on the C/N barrel change)
  • Mamiya's C-era brochure: 7 elements in 6 groups, 47° angle of view, f/22 minimum, 0.7 m closest focus, 67 mm filter, screw-in hood, 59 mm long, 75.5 mm diameter, 420 g
  • Needs its own hood: the Sekor C instruction sheet lists the 80mm f/1.9 among the lenses that take a special hood, even though the thread size is shared

Mamiya-Sekor C 80mm f/1.9 N:

  • N after the aperture on the name ring; plastic aperture ring in place of the metal one (Wikipedia)
  • Mamiya's N-era instruction sheet repeats the C figures: 7 elements in 6 groups, 47°, 70 cm, 67 mm filter, 59 × 75.5 mm, 420 g; the barrel change did not alter size or weight
  • Japanese dealers list it as 'SEKOR C 80mm F1.9 New'

Specifications

Construction
7 elements / 6 groups
Aperture range
f/1.9–f/22
Diaphragm blades
6
Min. focus
0.7 m
Dimensions
75.5 × 59 mm
Weight
420 g
Filter
67 mm
Years manufactured
1976
Country
Japan
Coating
Multicoated: the C in Sekor C is Mamiya's multicoating mark; the N lenses carry revised coatings (Wikipedia)

What reviewers say

Optical Ratings

Aggregated from the reviews above — follow the links for the full picture.

Spherical aberration
sharp wide open

History

The 80mm f/1.9 is the fast standard lens of the manual-focus Mamiya 645 system, and reviewers routinely call it one of the fastest lenses ever made for medium format. Mamiya’s own brochure gives it 7 elements in 6 groups, a 47° angle of view, f/22 minimum, 0.7 m closest focus, a 67 mm filter thread, 59 mm length, 75.5 mm diameter and 420 g: longer and heavier than the 80mm f/2.8 it sits beside (47 mm, 250 g), and with a bigger front. The M645 instruction manual lists both 80s as standard lenses and quotes the AE prism’s coupling range with the f/1.9 fitted, and Mamiya’s 1981 brochure sold the combination of this lens and the 1000S’s 1/1000 s top speed as one of the fastest medium-format cameras in the world.

When it appeared is not on the record consulted here. Modern Photography’s September 1975 report and its January 1976 test both list seven lenses for the new camera, with the 80mm f/2.8 as the only standard, and the f/1.9 is not among them; it is a standard-lens option in the M645 manual and with the M645 1000S of November 1976. The family year of 1976 is therefore the earliest year the lens is attested, not a documented release date, and that inference is stated as such above.

Two versions exist and the glass did not change between them. The original is engraved Sekor C with a metal aperture ring; the N of 1985, launched with the 645 Super, has an N after the aperture, a plastic aperture ring and revised coatings (Wikipedia). Mamiya’s N-era instruction sheet repeats every figure of the C brochure, 7/6, 70 cm, 67 mm, 59 by 75.5 mm and 420 g, so the two cannot be told apart by weight, only by the ring and the engraving. Japanese dealers list the later lens as the F1.9 New. Unlike the f/2.8, the f/1.9 was never made in a leaf-shutter N/L version.

Reviewers agree on the sharpness and split on the rendering. Aivaras on 35mmc finds it sharp even wide open but calls the bokeh rather nervous and the transition into the out-of-focus area a bit harsh; Blue Moon Camera’s test on a 645E reports crisp images with good contrast at f/1.9 and praises the damped rings and all-metal feel; Matt Osborne treats it as a portrait and low-light lens first, with the shallowest depth of field he has used in the format. All three note that at f/1.9 on 6×4.5 the depth of field is thin enough that focus technique matters more than the lens.

When buying: the 67 mm front and the 1:1.9 engraving separate it from the 58 mm f/2.8 at a glance; check that the A/M lever moves the diaphragm and that the meter coupler on the aperture ring is intact. Mamiya’s C-era instruction sheet warns that the lens needs its own hood, not the f/2.8’s, and that the No. 3 auto extension ring used with it must be the 3-S type to avoid vignetting. What remains open: the release year, any list price in yen or dollars, the blade count (only the Wikipedia table gives six), and the optical type, which no Mamiya document consulted names.

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 C 80mm f/1.9 (645)
M645 1000S with CdS prism and the Sekor C 80mm f/1.9 mounted, the Sekor C 45mm f/2.8 beside it (OverdeaR) — OverdeaR, via Wikimedia Commons (CC BY 2.0)
Sample photo taken with the Mamiya-Sekor C 80mm f/1.9 (645)
645 Pro TL with the Sekor C 80mm f/1.9 (Jes) — Jes from Melbourne, Australia, via Wikimedia Commons (CC BY-SA 2.0)
Sample photo taken with the Mamiya-Sekor C 80mm f/1.9 (645)
Front of the 80mm f/1.9 on a Mamiya 645 (Rémi Kaupp) — Rémi Kaupp, via Wikimedia Commons (CC BY-SA 3.0)

Sample photo wanted — shot with a Mamiya-Sekor C 80mm f/1.9 (645)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $600 across 19 fixed-price listings on 2026-09-19 (middle half $530–$690). First day tracked.

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

Show 58 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 C 110mm f/2.8 (645) · Mamiya-Sekor C 150mm f/3.5 (645) · Mamiya-Sekor C 45mm f/2.8 (645) · Mamiya-Sekor C 55mm f/2.8 (645) · Mamiya-Sekor C 80mm f/2.8 (645)

Sources (15)

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.