Mamiya 55mm f/2.8 Sekor C

The Mamiya Sekor C 55mm f/2.8 is a standard prime lens for the Phase One / Mamiya 645 mount, delivering a roughly 36mm full-frame equivalent field of view — a moderately wide perspective that works equally well for street, travel, and portrait shooting.

Key Specifications

• Focal length: 55mm (prime)
• Maximum aperture: f/2.8
• Lens type: Standard prime
• Mount: Phase One / Mamiya 645
• Format: Medium format 645
• Aperture range: f/2.8 maximum
• Use case: Allround, portrait, street
• Versions available: C (original), S, and N — each sold separately depending on availability

Who is the Mamiya Sekor C 55mm f/2.8 for?

If you shoot on a Mamiya 645 or a Phase One digital back and want one lens that handles almost anything, the Sekor C 55mm f/2.8 is the obvious starting point. The roughly 36mm equivalent field of view is wide enough to give you environmental context in portraits and street shots, yet tight enough that you're not constantly fighting with distortion. It's the kind of lens that stays on the camera — users consistently describe it as their most-reached-for optic in the 645 system.

f/2.8 on medium format also gives you noticeably smoother subject separation than you'd get at the same aperture on a smaller sensor, so low-light and shallow-depth-of-field work both punch above what the spec sheet implies. If you're already into the medium format world and are building out a kit, this is the standard prime that makes sense before you start adding specialty focal lengths like the Sekor C 35mm f/3.5 or longer portrait glass. It also sees a lot of use adapted to mirrorless systems — particularly Fujifilm GFX bodies — where it remains a compact and affordable way to get classic 645 rendering on a modern sensor.

Buying a used Mamiya Sekor C 55mm f/2.8

Picking up this lens second-hand is a straightforward decision for most 645 shooters. Mamiya built the Sekor C series to professional standards, so the glass and mechanics hold up well with age. At Camera-tweedehands.nl, every used lens is individually photographed, professionally inspected for optical and mechanical condition, and comes with a minimum of 12 months warranty. We verify the lens version (C, S, or N) and document any wear or marks so you know exactly what you're getting — no blind gambles on ageing glass.