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

Mamiya-Sekor C 210mm f/4 (645)

Mamiya · Mamiya 645 · 1975

Also known as: Mamiya-Sekor C 210mm f/4 · Mamiya Sekor C 210mm f4 · Mamiya 645 210mm f/4 · Mamiya 210mm f/4 N · Mamiya Sekor C 210mm f/4 N · Sekor C 210/4 · マミヤ セコールC 210mm F4 · マミヤ 645 210mm F4 · セコール C 210mm F4 N

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor C 210mm f/4 (metal-barrel C version) Mamiya 645 1975 — —
Mamiya-Sekor C 210mm f/4 N Mamiya 645 — — —
  1. Optical construction, angle of view, minimum aperture, closest focus, magnification, filter size, hood and dimensions are from Mamiya's own tables (the Sekor C instruction sheet at butkus.org and the 645 Interchangeable Lenses product sheet), and the 1981 M645 brochure agrees where it overlaps. The family weight is the N's 775 g from Mamiya's Pro-era sheet; the C version is 715 g in the 1981 brochure and the N-era sheet. Wikipedia's table repeats both figures.
  2. The family year rests on camera-wiki's list of the original 1975 lenses, the only source consulted that puts the 210 in the launch line-up; Mamiya's 1981 brochure confirms it existed by then. Japanese Wikipedia lists the セコールC 210mmF4 and 210mmF4N without a year for either.
  3. The blade count (9 per Wikipedia's table) is carried by one source and left out of the specifications. Wikipedia's 'peak resolution 77 at f/4' is unexplained there and not used.
How to tell them apart (expand)
  • Two versions, same optics: the letter N after the focal length, a plastic rather than metal aperture ring, and 775 g against 715 g are the documented differences
  • Built-in pull-out hood on both; 58 mm filter thread; f/32 minimum aperture; 2.5 m closest focus, the longest of the 645 primes short of the 300
  • Not the beige APO A 200mm f/2.8 (77 mm filters, 1,100 g), the Zoom ULD C 105–210mm f/4.5, or the autofocus 210mm f/4 ULD IF, which has no aperture ring

Mamiya-Sekor C 210mm f/4 (metal-barrel C version):

  • No N after the focal length; metal aperture ring
  • Mamiya's 1981 brochure: 5 elements, 19°, f/32 minimum, 8 ft closest focus, 58 mm filter, 129 mm equivalent, 715 g; the N-era Sekor C sheet gives the same 715 g at 137 × 70 mm

Mamiya-Sekor C 210mm f/4 N:

  • N engraved after the focal length; plastic aperture ring of the second-generation lenses (Wikipedia)
  • Mamiya's Pro-era table: 5 elements in 4 groups, 19°, f/4–32, 250 cm, 0.10×, 406 × 547 mm field, 58 mm filter, built-in hood, 137 × 70 mm, 775 g

Specifications

Construction
5 elements / 4 groups
Aperture range
f/4–f/32
Min. focus
2.5 m
Dimensions
70 × 137 mm
Weight
775 g
Filter
58 mm
Years manufactured
1975
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)

What reviewers say

Optical Ratings

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

Chromatic aberration
slight wide open
Optical formula

History

The 210mm f/4 is the long telephoto prime of Mamiya’s manual-focus 645 line below the 300, a 130mm equivalent on 35mm film by Mamiya’s table, and for most of the system’s life the cheapest way to that reach. Mamiya’s own figures: 5 elements in 4 groups, a 19° angle of view, f/4 to f/32, closest focus at 250 cm for 0.10×, a 58 mm filter thread, a built-in pull-out hood, and a barrel 70 mm across and 137 mm long. The weight depends on the version: 715 g for the metal-barrel lens in the 1981 brochure and the N-era sheet, 775 g for the N in the Pro-era product sheet. The Sekor C sheet at butkus.org prints a cross-section, which is linked above rather than copied.

Two versions exist and the glass did not change between them. The metal-ring Sekor C is on camera-wiki’s list of the original 1975 lenses and in Mamiya’s 1981 brochure. The N-era instruction sheet of about 1985, which already lists the 150 as the f/3.5N, still tabulates the 210 as a plain 210mm f/4 at 715 g, so the 210 was late to get the new barrel; by the 645 Pro book of 1992 it is the ‘210mm f/4N’ at 775 g, with the plastic aperture ring Wikipedia describes. Japanese Wikipedia dates neither version, and the year the N arrived is left unstated. Oldhand on MFlenses reckons the C-to-N improvements ‘appear most manifest in the shorter focal lengths’, which fits a lens whose optics are the same on both Mamiya tables.

The verdicts run from good to very good, with one outlier. Kristoffer Trolle, testing a Sekor C copy on an APS-C Fujifilm through a Rhinocam adapter, scored it 7 for sharpness wide open, 9 at f/11, 7 for rendition and 5 for bokeh, with the magenta tint and micro-contrast he found across the Mamiya lenses. The Japanese blog shigiphoto days, on an N copy, found solid rendering, clean colour, contrast better than the 105-210mm zoom, and slight fringing wide open at high contrast that stayed within tolerance. Lensvana calls it ‘sharp, underrated’ and prices it at about $100. In the Mamiya 645 Flickr group, mugley found it ‘plenty sharp enough’ with nicer bokeh than the faster lenses, while John Falkenstine’s older copy was ‘a dog’, and D1N0 on MFlenses saw only ‘very light CA’. The one complaint everyone shares is the 2.5 m closest focus, which Matt Fahrner on Flickr says makes it less useful than it looks.

When buying, the C and N differ only in barrel and 60 g; the ring and the engraving sort them. Check that the hood pulls out and stays out, that the A/M lever returns to A (Mamiya’s sheet warns that leaving it on M gives wrong exposure), that the aperture snaps shut at f/32, and that the focusing helicoid is not stiff over its long throw. The lens mounts on the 645AF, AFD and DF bodies but meters only stopped down there, per Wikipedia. It is not the beige APO A 200mm f/2.8 with 77 mm filters, nor the autofocus 210mm f/4 ULD IF with no aperture ring, and Wikipedia’s table lists the AF lens in the same row family, so read seller titles closely.

What remains open: the year the N barrel replaced the C, a launch price in any currency, a discontinuation date, and the blade count beyond Wikipedia’s figure of nine.

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 210mm f/4 (645)
Mamiya-Sekor C 210mm f/4 (Gürkan Sengün) — Gürkan Sengün, via Wikimedia Commons (CC BY-SA 3.0)
Sample photo taken with the Mamiya-Sekor C 210mm f/4 (645)
Dave Weckl, Lisbon 2009: Mamiya M645 1000S, Sekor 210mm f/4, Ilford Delta 3200 (Ivo Fechner Baião) — Ivo Fechner Baião, via Wikimedia Commons (CC BY-SA 2.0)

Sample photo wanted — shot with a Mamiya-Sekor C 210mm f/4 (645)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $95 across 56 fixed-price listings on 2026-10-19 (middle half $74–$120). Tracked since 2026-09-21, 6 days: up 1% from $94.

By day
DateMedianMiddle halfListings
2026-10-19$95$74–$12056
2026-10-18$95$74–$12056
2026-10-17$95$74–$12056
2026-10-16$95$74–$12058
2026-10-15$95$74–$12056
2026-09-21$94$71–$12058

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

Show 89 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 2026-10-19. Links go to the shop or marketplace that carries the item.

Related: Mamiya-Sekor C 150mm f/3.5 (645) · Mamiya A 150mm f/2.8 (645) · Mamiya APO A 200mm f/2.8 (645) · Mamiya-Sekor C 300mm f/5.6 (645) · Mamiya-Sekor Zoom C 105-210mm f/4.5 (645) · Mamiya APO A 300mm f/2.8 (645) · Mamiya-Sekor C 500mm f/5.6 (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.