Mamiya's ultra-wide for the RB67 — the Sekor C 50mm f/4.5 giving a dramatic wide perspective on 6x7.
The Mamiya Sekor C 50mm f/4.5 is an ultra-wide lens for the Mamiya RB67 medium format system. On the 6x7 format, 50mm provides approximately a 25mm equivalent — a dramatically wide perspective. The C designation indicates multi-coating. It was the widest standard lens available for the RB67 system, essential for architectural and interior photography.
Optical performance is good for the extreme wide angle on medium format. Sharpness is very good when stopped down. The ultra-wide perspective on 6x7 creates dramatic images with extraordinary resolution from the large negative. Distortion is moderate and well-controlled for the focal length. The built-in leaf shutter enables flash sync at all speeds.
Mamiya RB mount with integrated leaf shutter. Filter thread varies by version. Weight is substantial — the RB system is inherently heavy. Build quality is professional grade. Manual focus with bellows focusing on the RB67 body. The leaf shutter is a significant advantage for architectural and interior work requiring flash lighting.
Available on the used market at moderate prices. Check leaf shutter operation across all speeds and clean optics. An essential lens for RB67 photographers shooting architecture, interiors, and dramatic landscape perspectives. The ultra-wide on 6x7 medium format produces images with a unique character unavailable from smaller formats.