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

Mamiya-Sekor C 150mm f/4 (645)

Mamiya · Mamiya 645 · 1975 · 5 elements in 4 groups (Wikipedia table)

single source, unconfirmed

Also known as: Mamiya-Sekor C 150mm f/4 · Mamiya Sekor C 150mm f4 · Mamiya 645 150mm f/4 · Mamiya M645 150mm 4 · Sekor C 150/4 · マミヤ セコールC 150mm F4 · マミヤ645 150mm F4

Variants & identification

Variant Mount Years Serial ranges Production
Mamiya-Sekor C 150mm f/4 Mamiya 645 1975 — —
  1. Every figure in the table (5 in 4, f/4–32, 6 blades, 1.5 m, 58 mm, built-in hood, 91 × 70 mm, 440 g, 52 lines/mm at f/4) comes from the English Wikipedia lens table alone. camera-wiki confirms only that a C 150mm f/4 existed, and Japanese Wikipedia's 645 list has no 150mm f/4 (its SFC 150mm F4 is the RB67 lens). The page carries the single-source flag; no Mamiya document consulted prints a row for it, the Sekor C instruction sheet's table being image-only.
  2. No source consulted dates the lens. The year is the C line's start with the M645 (June 1975, Japanese Wikipedia), on camera-wiki's placing of it in the original list. It is not in the 645 Pro TL book of 1997.
  3. The Sekor C 150mm f/3.5 (5 elements in 5 groups, C and N barrels) is a different lens at the same focal length, as are the A 150mm f/2.8 and the leaf-shutter A 150mm f/3.8 N/L; the SF C 145mm f/4 is the soft-focus lens. All are excluded from this page's listings by aperture.
How to tell them apart (expand)
  • 1:4 on the name ring sorts it from the f/3.5, f/2.8 and f/3.8 150s; 5 elements in 4 groups against the f/3.5's 5 in 5 (Wikipedia table)
  • Built-in hood and 58 mm thread, like the f/3.5; 440 g, 25 g heavier than the C f/3.5's 415 g by the same table
  • One version only, C; no N barrel is recorded by any source consulted

Mamiya-Sekor C 150mm f/4:

  • Name ring reads Mamiya-Sekor C 150mm 1:4, with nothing after the aperture; metal-barrel C lens, no N version recorded
  • Built-in sliding hood, 58 mm filter thread, 91 mm long, 70 mm across, 440 g (Wikipedia table); the f/3.5 that replaced it is also 58 mm but 5 elements in 5 groups
  • f/4 to f/32, six aperture blades, closest focus 1.5 m (Wikipedia table)

Specifications

Formula
5 elements in 4 groups (Wikipedia table)
Construction
5 elements / 4 groups
Aperture range
f/4–f/32
Diaphragm blades
6
Min. focus
1.5 m
Dimensions
70 × 91 mm
Weight
440 g
Filter
58 mm
Years manufactured
1975
Country
Japan
Coating
Multi-coated: the C in Sekor C is Mamiya's multicoating mark (Wikipedia), and Mamiya's Sekor C sheet says all the lenses for the M645 have been multi-coated

What reviewers say

No reviews aggregated yet — this family is still in the research queue. Written one? We'd love to index it.

History

The Sekor C 150mm f/4 is the first of the manual-focus 645’s four 150s, the slow short telephoto of the early C line: a 93 mm equivalent on 35mm film, 5 elements in 4 groups, f/4 to f/32 with six blades, 1.5 m closest focus, a 58 mm filter thread and a built-in sliding hood in a barrel 91 mm long, 70 mm across and 440 g. Those figures, and a peak resolution of 52 lines per mm at f/4, come from the English Wikipedia lens table and from nowhere else consulted; camera-wiki’s list of the original C lenses confirms that a ‘C 150mm f4’ existed, and Japanese Wikipedia’s 645 section does not list a 150mm f/4 at all. Mamiya’s own Sekor C instruction sheet prints its specification table as an image, so the page carries the single-source flag until a Mamiya brochure row can be read.

It has one version and no date. On camera-wiki’s placing of it among the original lenses the year here is the C line’s start with the M645 in June 1975, a floor rather than a launch date. It was replaced by the Sekor C 150mm f/3.5, a different lens of 5 elements in 5 groups that shares the 58 mm thread and built-in hood and weighs 415 g by the same table; the f/3.5 went on to an N barrel in the 645 Super years, and the 645 Pro TL book of 1997 lists the f/3.5 N, the A 150mm f/2.8 and the leaf-shutter A 150mm f/3.8 N/L with no f/4. When the f/4 left production is not recorded anywhere consulted.

No review of this lens was found by the searches made for this page. It is the lens a seller often means by ‘Mamiya 645 150mm’ with no aperture given, which is why this page’s listings require an f/4 in the title and exclude the other three apertures.

When buying, slide the built-in hood out and back to check it has not been dented, run the aperture to f/32 and confirm the A/M lever stops the lens down, and look at the meter coupler on the aperture ring, which the metered prisms read. Read the name ring before paying: 1:4 is this lens, 1:3.5 the later one, and the SF C 145mm f/4 is a soft-focus lens with a second control ring. What remains open: a Mamiya specification row to confirm the Wikipedia figures, the launch and discontinuation years, a list price in any currency, and an independent test.

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 C 150mm f/4 (645)? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $180 across 4 fixed-price listings on 2026-11-02 (middle half $150–$180). 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 2026-11-02. 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 A 150mm f/3.8 N/L (645) · Mamiya-Sekor SF C 145mm f/4 Soft Focus (645) · Mamiya-Sekor C 210mm f/4 (645)

Sources (5)

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.