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

Mamiya-Sekor Zoom C 55-110mm f/4.5 N (645)

Mamiya · Mamiya 645 · 1984

single source, unconfirmed

Also known as: Mamiya-Sekor Zoom C 55-110mm f/4.5 N · Mamiya Sekor C 55-110mm f4.5 N · Mamiya 645 55-110mm f/4.5 · Mamiya 55-110mm f/4.5 N · Sekor C 55-110/4.5 · マミヤ セコールC ズーム 55-110mm F4.5 N · マミヤ 645 55-110mm F4.5

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor Zoom C 55-110mm f/4.5 N Mamiya 645 1984 — —
  1. Optical construction, angle of view, minimum aperture, closest focus, magnification, filter size, hood, dimensions and weight are from Mamiya's own 645 Interchangeable Lenses product sheet (645 Pro era). Wikipedia and Kamerastore both give 800 g against Mamiya's 780 g; the maker's figure is used.
  2. The 1984 date rests on Kamerastore's listing alone, so the page carries the single-source flag. It fits the record: the lens is missing from Mamiya's Sekor C instruction sheet, which lists the N lenses 'developed lately for M645 SUPER' (December 1985), and present in the later product sheet, but no Mamiya document consulted dates it.
  3. The blade count is left absent: Wikipedia says 8 and Kamerastore says 6, and Mamiya's table gives none.
  4. The Mamiya AF 55-110mm f/4.5 for the 645 AF bodies shares the 11-in-10 construction, 1.5 m closest focus and 67 mm filter (Japanese Wikipedia) but has the autofocus bayonet; it is a different system and is excluded from this page's listings.
How to tell them apart (expand)
  • 67 mm filter thread and a screw-in hood; the 105-210 ULD and 300 take 58 mm
  • 780 g and 104 mm long by Mamiya's table, the shortest and lightest of the three 645 zooms
  • One version only, always marked N; a 55-110 without the N on the ring is the autofocus lens

Mamiya-Sekor Zoom C 55-110mm f/4.5 N:

  • Name ring reads Mamiya-Sekor Zoom C 55-110mm 1:4.5 N; the only version, so every example carries the N
  • Mamiya's table: 11 elements in 10 groups, 65°–35° angle of view, f/4.5–32, 150 cm closest focus, 0.04–0.08×, 67 mm filter, screw-in hood, 104.2 × 77.2 mm, 780 g
  • Separate zoom and focus rings (Mamiya's Pro manual lists it as 'Zoom 55-110mm f/4.5N')

Specifications

Construction
11 elements / 10 groups
Aperture range
f/4.5–f/32
Min. focus
1.5 m
Dimensions
77.2 × 104.2 mm
Weight
780 g
Filter
67 mm
Years manufactured
1984
Country
Japan
Coating
Multi-coated: Mamiya's sheet says all the lenses for the M645 have been multi-coated, and the C in Sekor C denotes multicoating (Wikipedia)

What reviewers say

Optical Ratings

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

Chromatic aberration
corners, correctable
Flare & ghosting
hazy wide open
Optical formula

Mamiya's 645 Interchangeable Lenses product sheet tabulates 11 elements in 10 groups but prints no cross-section, and the M645 1000S manual and Sekor C sheet, which do print cross-sections, predate this lens. No Mamiya document with a diagram for it was found.

History

The 55-110mm f/4.5 N is the standard zoom of Mamiya’s manual-focus 645 system, a 34–68mm equivalent on 35mm film by Mamiya’s table, and the only zoom in the line that reaches wider than the 80mm normals. Mamiya’s own figures: 11 elements in 10 groups, angles of view from 65° to 35°, a constant f/4.5 to f/32, closest focus at 150 cm for 0.04× to 0.08×, a 67 mm filter thread with a screw-in hood, and 780 g in a barrel 77 mm across and 104 mm long. No Mamiya document consulted prints a cross-section for it.

It has one version and it was born an N. The N lenses, by Mamiya’s Sekor C instruction sheet, were ‘developed lately for M645 SUPER’, the body of December 1985, and the 55-110 is missing from that sheet’s table and present in the later 645 Pro-era product sheet and in the 645 Pro manual’s list. Kamerastore’s listing says 1984, which fits that record but is the only date found, so the page carries the single-source flag. The autofocus Mamiya AF 55-110mm f/4.5 that followed on the 645 AF bodies has the same 11-in-10 construction, 1.5 m close focus and 67 mm thread by Japanese Wikipedia, but it is a different mount; a 55-110 without the N on its ring is the AF lens.

The reviewers are lukewarm. Tony Howell, on a 39-megapixel P45 back, found it ‘milky’ wide open, best at f/8, where the centre nearly matched his 120mm macro, better at the long end than at 55mm, and average in the corners with colour fringing at every aperture that software removes; he gave it 6 out of 10, a useful range that ‘could be much better’, and pointed large-sensor users to primes. Teo Totev, shooting at its close-focus limit on a Leaf Aptus 75, scored it 5 for sharpness and 5 for bokeh, his ‘Good’ tier, well below the 110mm f/2.8 he rates a 9. Carlo Kopp’s gallery shows it on Nikon bodies without a verdict. On film at f/8 to f/11 the consensus is that it does the job of a 55, an 80 and a 110 in one barrel at the cost of two stops and some corner quality.

When buying, work both rings through their travel: the zoom and focus rings are separate, and old grease stiffens the zoom first. Check for haze between the many groups, that the Auto/Manual lever is back on A, and that the aperture blades snap shut at f/32. It mounts on the 645AF and later bodies but meters only stopped down there. Because the AF zoom shares the numbers, read the name ring before paying.

What remains open: a second source for the 1984 date, the blade count (Wikipedia says 8, Kamerastore 6, Mamiya nothing), a list price in any currency, and a discontinuation date.

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 55-110mm f/4.5 N (645)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $180 across 17 fixed-price listings on 2026-09-21 (middle half $160–$190). First day tracked.

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

Show 6 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 2026-09-21. Links go to the shop or marketplace that carries the item.

Related: Mamiya-Sekor Zoom C 105-210mm f/4.5 (645) · Mamiya-Sekor C 55mm f/2.8 (645) · Mamiya-Sekor C 80mm f/2.8 (645) · Mamiya-Sekor C 110mm f/2.8 (645)

Sources (11)

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.