Mamiya's RZ67 wide-angle — the electronic leaf-shutter Sekor Z 50mm f/4.5 W for 6x7.
The Mamiya Sekor Z 50mm f/4.5 W is a wide-angle lens for the Mamiya RZ67 medium-format system, introduced with the RZ67 in 1982. The Z designation marks the RZ67 lens line, which succeeded the RB67 with electronic leaf shutters. The W denotes its wide-angle designation. On the 6x7 frame the 50mm gives a wide field of view.
This is a manual-focus lens native to the Mamiya RZ67 bayonet mount, with a focal length of 50mm and a maximum aperture of f/4.5. It contains an electronically timed leaf shutter controlled by the RZ67 body, with the aperture set on the barrel and focusing by the camera bellows. The design covers the full 6x7 image circle.
At 50mm on 6x7 the angle of view corresponds to roughly a 24-25mm lens on 35mm, a genuine wide perspective suited to interiors, architecture and landscape. The electronic leaf shutter integrates with the RZ67's metering and allows flash sync at all speeds. The lens holds even sharpness across the large frame when stopped down, favouring deliberate tripod-based work.
The RZ67 Z 50mm f/4.5 W is a common studio and landscape wide-angle and appears regularly on the used market. Because its leaf shutter is electronic, confirm it fires correctly at all speeds with a working body and watch for erratic behaviour. Inspect the glass for haze and fungus, confirm the aperture is dry, and verify the bayonet and electrical shutter coupling engage properly.