Mamiya Mamiya-Sekor C 180mm f/4.5

TelephotoMount: Mamiya RB180mmf/4.5 – f/32
Introduced: 1974

Mamiya Sekor C 180mm f/4.5 is the portrait telephoto for the Mamiya RB67 system — equivalent to roughly a 90mm field of view in 35mm terms. Compresses background distance for the classic medium-format-portrait look while remaining handholdable on the heavy RB67 body (with care).

Key features

  • Mamiya RB bayonet — fits all RB67 bodies
  • Built-in Seiko leaf shutter — 1s to 1/400, X-sync at all speeds
  • 77mm filter thread (KL version: 77mm; C version varied)
  • 5-element/4-group optical formula with single coating
  • Close-focus via body bellows
  • Manual aperture + manual focus

Use case + rendering

The 180mm Sekor C is the portrait + tight-landscape lens for RB67. At f/4.5 wide open it produces shallow but not paper-thin DoF on 6×7 — about equivalent to f/2.4 on 35mm in DoF terms. Background separation is smooth thanks to the leaf-shutter aperture (typically rounded blades) and the long focal length.

For tighter portraits or true telephoto compression, Mamiya offered a 250mm and 360mm Sekor C — but the 180mm is the most-used portrait lens because it balances reach with handheld practicality.

Compatible bodies

Related lenses