Mamiya-Sekor 100mm f/2.8 (Press)
Mamiya · Mamiya Press · 1967
single source, unconfirmedAlso known as: Mamiya Press 100mm f/2.8 · Mamiya Press 100mm f2.8 · Mamiya-Sekor 100mm f/2.8 · Mamiya Sekor 100mm f2.8 Universal · Mamiya Universal 100mm f2.8 · Mamiya Super 23 100mm f2.8 · Sekor 100/2.8 Press · マミヤプレス 100mm F2.8 · マミヤ セコール 100mm F2.8 · セコール 100mm F2.8
Variants & identification
| Variant | Mount | Years | Serial ranges | Production |
|---|---|---|---|---|
| Mamiya-Sekor 100mm f/2.8 (chrome-plated type, time lever) · Seikosha-S #0, B and 1s–1/500, M-X sync; time lever holds the blades open at B | Mamiya Press | 1967 | — | — |
| Mamiya-Sekor 100mm f/2.8 (black-finished type, press focus) · Seikosha #0 (Seiko #0 in the later manual), B and 1s–1/500, M-X sync; press-focus lever holds the blades open | Mamiya Press | 1969 | — | — |
- Element and group counts, picture angles (53°30' on 6×9, 47°30' on 6×7), minimum aperture, filter size, hood and shutter-arresting methods are from Mamiya's own tables: the Super 23 manual (p.51), the 1969 Universal manual (p.18), the Universal Lenses booklet and the later Universal manual (p.46).
- Closest focus of 1.0 m is the first column of the Super 23 manual's metric depth-of-field table for the 100mm f/2.8 and Japanese Wikipedia's figure; English Wikipedia gives 3.5 ft (1.1 m), the first column of the Universal manual's table in feet. No maker document states it as a specification.
- Weight of 700 g is English Wikipedia's and camera-wiki's figure; no Mamiya document consulted gives a weight for the 100mm f/2.8. The Universal manual's 480 g is the 100mm f/3.5, a different lens and a different page.
- Years: 1967 is the Super 23 manual's, the earliest document listing the lens; no source gives a launch month or a discontinuation date. The chrome and black variants are dated by the documents that first show them, not by any published changeover.
- Shutter name: Seikosha-S #0 in the Super 23 manual, Seikosha #0 in the 1969 Universal manual, Seiko #0 in the later one; camera-wiki says the chrome lenses have the Seikosha-S and the later ones the Seiko #0.
How to tell them apart
- Two finishes of one lens: chrome front-reading speed dial with a time lever, or black side-reading dial with a press-focus lever; glass, angles, f/32 minimum, 72 mm filter and clamp-on hood are the same
- Large front element for the range and a 72 mm thread shared with the 50 and 75; the retracting 100mm f/3.5 has 55 mm (black) or 40.5 mm (chrome) and is a different page
- Does not retract: the Super 23 table marks the 100mm f/2.8 as no retraction, where the 100mm f/3.5 must be pulled out before shooting
- Rangefinder coupled and framed with the camera's own 100mm bright line on the Super 23 and Universal
Mamiya-Sekor 100mm f/2.8 (chrome-plated type, time lever):
- Chrome-plated shutter speed dial read from the front; blades held open for the ground glass by the time lever at B, the method the Super 23 manual gives for the 100mm f/2.8
- Listed among the chrome-plated-type lenses with the 65, 90 and 150 in the Universal Lenses booklet (p.2); 72 mm filter thread and clamp-on hood, the same as the black lens
Mamiya-Sekor 100mm f/2.8 (black-finished type, press focus):
- Black-finished scale ring and side-reading speed dial; press-focus lever that holds the blades open after cocking, as on the black 100mm f/3.5, 127 and 150 (Universal Lenses booklet p.3)
- Same 6-element glass, 53°30' and 47°30' angles, f/32, 72 mm thread and clamp-on hood as the chrome lens
- Mamiya-Sekor 100mm f/2.8 (chrome-plated type, time lever): The first form of the lens, in the Super 23 manual of 1967 with a T-setting shutter. Both Universal manuals list the 100mm f/2.8 in chrome and black with the same glass, angles, filter and hood; only the shutter-arresting method differs.
- Mamiya-Sekor 100mm f/2.8 (black-finished type, press focus): The black type appears with the 1969 Universal documents, which list the 100mm f/2.8 in both finishes (double asterisk for black, single for chrome in the 1969 table; Black and Chrome in the later manual). The year is the Universal's; no source gives the changeover date, and the two finishes overlapped.
Specifications
- Formula
- 6 elements in 4 groups, double Gauss (Super 23 and Universal manuals for the counts; English Wikipedia calls it Planar-type, camera-wiki Biotar-type)
- Construction
- 6 elements / 4 groups
- Aperture range
- f/2.8–f/32
- Shutter
- Seikosha-S #0 leaf shutter in the lens (Seikosha #0, then Seiko #0, in the Universal manuals): B and 1s–1/500, cocked by a lever on the barrel, M-X flash sync at every speed; the chrome lens holds the blades open with a time lever at B, the black lens with a press-focus lever
- Min. focus
- 1 m
- Weight
- 700 g
- Filter
- 72 mm
- Years manufactured
- 1967
- Country
- Japan
What reviewers say
- Andrew Welsh, Shoot It With Film (Universal Press review) (blog) — The lens you really want with this system: worth every penny for the extra bokeh and the faster shutter speeds it allows, against the ubiquitous 100mm f/3.5 that comes with most kits.
- Greg, Camera Reflections (50, 65, 75 and 100 compared) (blog) — The premium standard lens: sharp throughout its range, with very nice bokeh from the double-Gauss design and the only real shallow depth of field in the system.
- Kai Lietz, 35mmc (5 frames with a Super 23) (blog) — Shoots the 100mm f/3.5 and wants the f/2.8 and the 50 as great performers; in the comments Joe Finocchi, who compared the two 100s, found the f/3.5 sharper in the centre stopped down and the f/2.8 more even to the edges, sharp enough for 300-person group photographs.
Optical formula — 6 elements in 4 groups, double Gauss (Super 23 and Universal manuals for the counts; English Wikipedia calls it Planar-type, camera-wiki Biotar-type)
History
The 100mm f/2.8 is the fast standard lens of the Mamiya Press, the alternative to the retracting 100mm f/3.5 that came with the Super 23 and the Universal. Mamiya’s tables give 6 elements in 4 groups, and the cross-section printed in the Super 23 manual and the Universal booklets shows a double Gauss with cemented pairs either side of the diaphragm, which English Wikipedia calls a Planar type and camera-wiki a Biotar type. The angles of view are 53°30’ on 6×9 and 47°30’ on 6×7, the same as the f/3.5 lens; the aperture runs to f/32, the filter thread is 72 mm with a clamp-on hood, and the lens does not retract. Closest focus is 1.0 m, the first column of the Super 23 manual’s metric depth-of-field table and the figure Japanese Wikipedia prints. The weight is 700 g by the Wikipedia and camera-wiki figure, since no Mamiya document gives one; the 480 g in the Universal manual is the f/3.5.
There are two finishes and they differ only at the shutter. The chrome-plated type, which is how the Super 23 manual of 1967 describes the lens, has a chrome speed dial read from the front and holds its blades open for the ground glass with a time lever at B; the black-finished type, which arrives with the 1969 Universal documents, has a black scale ring, a side-reading dial and a press-focus lever that holds the blades open after cocking, the same lever as the black 100mm f/3.5, 127 and 150. Both Universal manuals list the 100mm f/2.8 in both finishes with the same glass, angles, filter and hood, and the Universal Lenses booklet gives shutter instructions for each. The shutter is the Seikosha-S #0, B and 1 to 1/500 second with M and X sync at every speed; the later manual calls it the Seiko #0, which is the maker’s renaming and not a different mechanism. No source gives a changeover date between the finishes or a discontinuation date for the lens.
The reviewers are of one mind about which 100 to buy. Andrew Welsh at Shoot It With Film calls the f/2.8 the lens you really want with the system, worth every penny for the extra bokeh and the faster shutter speeds, against the f/3.5 that comes in most kits. Greg at Camera Reflections calls it the premium standard lens, sharp throughout its range with very nice bokeh from the double-Gauss design, the only lens in the range that gives real subject separation. Theo Panagopoulos at Photo Thinking, shooting the f/3.5, calls the f/2.8 the sought-after one. The only comparison found is in the comments under Kai Lietz’s 35mmc piece, where Joe Finocchi reports the f/3.5 sharper in the centre stopped down and the f/2.8 more even to the edges, good enough for 300-person group photographs. Nobody consulted has tested it wide open in print.
When buying, decide which shutter arrangement suits the work: the black lens’s press-focus lever is quicker for ground-glass use, the chrome lens’s time lever needs the dial at B. Run the shutter through its speeds, since the slow ones drag first on a Seikosha of this age, try the lever and confirm it returns and closes the blades, and check the M-X switch. Look through a front element that is large for the range for haze and cleaning marks, and check the rear group for separation. The lens shares its 72 mm thread and clamp-on hood with the 50 and 75, so filters carry over. No list price in yen or dollars was found for the 100mm f/2.8, no production figures and no serial-number scheme; the weight is Wikipedia’s, not Mamiya’s.
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.
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