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

Mamiya-Sekor C 110mm f/2.8 (645)

Mamiya · Mamiya 645 · 1976

single source, unconfirmed

Also known as: Mamiya-Sekor C 110mm f/2.8 · Mamiya Sekor C 110mm f2.8 · Mamiya 645 110mm f/2.8 · Mamiya 110mm f/2.8 N · Mamiya Sekor C 110mm f/2.8 N · Sekor C 110/2.8 · マミヤ セコールC 110mm F2.8 · マミヤ 645 110mm · セコール C 110mm F2.8 N

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor C 110mm f/2.8 (1976 baseline) Mamiya 645 1976–1985 — —
Mamiya-Sekor C 110mm f/2.8 N Mamiya 645 1985 — —
  1. Optical construction, angle of view, minimum aperture, closest focus, magnification, filter size, hood, dimensions and weight are from Mamiya's own tables: the Mamiya-Sekor C Interchangeable Lenses sheet (M645 Super era, at butkus.org) and the later Mamiya 645 Interchangeable Lenses sheet. Both give the same figures for the 110mm N; neither prints a cross-section.
  2. The 1976 date for the first version rests on Japanese Wikipedia alone, hence the single-source flag. The 1985 start of the N follows Mamiya's statement that the N lenses were developed for the M645 Super, which Japanese Wikipedia dates to December 1985. A Flickr Mamiya 645 group thread instead says the N line came with the 645 Pro (1992); the maker's own sheet is preferred here.
  3. Some dealer listings describe the 110mm N as 6 elements in 5 groups. Every Mamiya document and both Wikipedias give 5 in 5, which is what this page carries.
How to tell them apart (expand)
  • Two versions, same glass: the letter N after the focal length is the only optical-irrelevant difference Mamiya documents; C is all-metal, N has a plastic aperture ring
  • Not a leaf-shutter lens: the 645's focal-plane shutter does the work, and there is no shutter-speed ring on the barrel
  • Not the 645 AF lens: the manual-focus 110 has a focusing ring with a depth-of-field scale and an A-M lever; the autofocus 110mm f/2.8 (AF, D, LS) has neither and takes 72 mm filters (Wikipedia)
  • Not the RZ67's Sekor Z 110mm f/2.8 W, which is a leaf-shutter lens with a 77 mm filter thread (Japanese Wikipedia)

Mamiya-Sekor C 110mm f/2.8 (1976 baseline):

  • No N after the focal length on the name ring
  • All-metal barrel with a metal aperture ring; the N that replaced it uses plastic for the aperture ring (Wikipedia; GetDPI forum)
  • Auto/Manual (A-M) change lever for depth-of-field preview and the meter coupler on the rear, as on every M645 lens (Mamiya instruction sheet)

Mamiya-Sekor C 110mm f/2.8 N:

  • N engraved after the focal length on the name ring
  • Plastic aperture ring and the restyled barrel of the second-generation lenses (Wikipedia)
  • Mamiya's own table: 5 elements in 5 groups, 35° angle of view, f/2.8–22, 120 cm closest focus, 0.11×, 58 mm filter, screw-in hood, 60 × 70 mm, 390 g

Specifications

Construction
5 elements / 5 groups
Aperture range
f/2.8–f/22
Min. focus
1.2 m
Dimensions
60 × 70 mm
Weight
390 g
Filter
58 mm
Years manufactured
1976
Country
Japan
Coating
Multi-coated on both versions: Mamiya's sheet says 'all the lenses for the M645 have been multi-coated', and the C in Sekor C denotes multicoating (Wikipedia); the N is reported to carry revised coatings

What reviewers say

Optical Ratings

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

Spherical aberration
sharp wide open
Optical formula

Mamiya's two lens sheets consulted (the Sekor C instruction sheet at butkus.org and the 645 Interchangeable Lenses product sheet) tabulate 5 elements in 5 groups but print no cross-section, and no other Mamiya document with a diagram for this lens was found.

History

The 110mm f/2.8 is the short portrait lens of Mamiya’s manual-focus 645 system, the equivalent of a 68mm on 35mm film by Mamiya’s own reckoning. It arrived in 1976, a year after the M645 body of June 1975, according to Japanese Wikipedia’s product list, and it stayed in the catalogue through the M645 1000S, the M645 Super of December 1985 and the 645 Pro. Mamiya’s tables give 5 elements in 5 groups, a 35° angle of view, apertures from f/2.8 to f/22, closest focus at 120 cm for a 0.11× magnification, a 58 mm filter thread, and 390 g in a barrel 60 mm across and 70 mm long. It shares its screw-in hood with the 80mm f/2.8. No Mamiya document consulted names the design type or prints a cross-section.

There are two versions and the glass is the same in both. The first is the Sekor C, an all-metal lens with the Auto/Manual change lever for previewing depth of field and the meter coupler that every M645 lens carries. The second is the Sekor C N, which Mamiya’s instruction sheet describes as the lens ‘developed lately for M645 SUPER’ and usable on the earlier M645 and 1000S bodies. Wikipedia calls the N a cosmetic redesign, with a plastic aperture ring where the C had metal; a GetDPI forum contributor adds that the N lenses have different coatings and make heavier use of plastics while the formula is unchanged. The C in Sekor C already meant multicoating: the sheet says all the M645 lenses are multi-coated to suppress flare and ghosting.

Reviewers agree the lens is sharp, including wide open, and disagree about the background. Teo Totev’s test on a Phase One DF with a Leaf Aptus 75 back scores it 9 for sharpness and 6 for bokeh, the same sharpness he gives the best autofocus lenses. Lensvana’s guide calls it very sharp with ‘unusual bokeh that can read as harsh or creative depending on taste’. Forum owners on MFlenses praise the uniform out-of-focus rendering but warn that straight lines in the background come out as drawn lines; the GetDPI poster who paid $104 for a C called the bokeh ‘jittery, not buttery’ and kept the lens anyway. The 1.2 m minimum focus is the practical limit for tight head shots, and Mamiya Love group members suggest extension rings or the 150mm instead.

Buying one means separating it from three other Mamiya 110s. The RZ67’s Sekor Z 110mm f/2.8 W is a leaf-shutter lens with a 77 mm filter thread and no place on a 645 body. The autofocus 110mm f/2.8 for the 645AF, AFD and DF bodies has no focusing scale or A-M lever and takes 72 mm filters. The manual-focus lens does mount on those autofocus bodies, but Wikipedia notes it then meters only stopped down. On the lens itself, check that the A-M lever returns to A (Mamiya warns that leaving it on M gives wrong exposure), that the aperture snaps closed, and that the focusing ring turns without the stiffness the MFlenses thread reports from dried lubricant.

What remains open: a launch price in yen or dollars, which no source consulted gives; a discontinuation date for the N; the 1976 date itself, which rests on Japanese Wikipedia alone; and whether the N’s coatings differ from the C’s in any way Mamiya ever documented.

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 110mm f/2.8 (645)
Mamiya-Sekor C 110mm f/2.8 (Gürkan Sengün) — Gürkan Sengün, via Wikimedia Commons (CC BY-SA 3.0)
Sample photo taken with the Mamiya-Sekor C 110mm f/2.8 (645)
Mamiya-Sekor C 110mm f/2.8, side view (Gürkan Sengün) — Gürkan Sengün, via Wikimedia Commons (CC BY-SA 3.0)

Sample photo wanted — shot with a Mamiya-Sekor C 110mm f/2.8 (645)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $430 across 16 fixed-price listings on 2026-09-19 (middle half $350–$480). First day tracked.

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

Show 30 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 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/1.9 (645) · Mamiya-Sekor C 80mm f/2.8 (645)

Sources (10)

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.