Mamiya's long RB67 tele — the leaf-shutter Sekor C 360mm f/6.3 for 6x7 reach.
The Mamiya Sekor C 360mm f/6.3 is a long telephoto lens for the Mamiya RB67 medium-format system, from the C-series line. It is among the longest RB67 primes, built for photographers needing extended reach on the 6x7 format. Its size and specialised role kept it a comparatively uncommon item in the catalogue.
This is a manual-focus lens native to the Mamiya RB67 bayonet mount, with a focal length of 360mm and a maximum aperture of f/6.3. It carries a built-in leaf shutter, with the aperture set on the barrel and focusing driven by the camera bellows. The optical design covers the full 6x7 image circle across a narrow angle of view.
At 360mm on 6x7 the perspective corresponds to roughly a 175-180mm lens on 35mm, a long reach with the compression telephotos are valued for. The f/6.3 aperture is modest but reasonable for a lens of this length, and firm tripod support is essential to realise its sharpness. It suits distant landscape detail, environmental subjects and longer-range portraiture.
The 360mm f/6.3 is scarce on the used market and appeals to a specialist audience. Test the leaf shutter across all speeds for clean firing, and inspect the large glass elements for haze, fungus and separation. Confirm the aperture blades are dry and close cleanly, check any tripod support for security, and verify the bayonet and shutter coupling before buying.