<ul> <li>Front side - M42x1 female thread</li> <li>Rear side - Mamiya 645 mount</li> </ul> <p>This adapter allows using M42 lenses on Mamiya 645 cameras. No infinity focus provided. Just mechanical coupling.</p> <p><strong>IMPORTANT NOTE:</strong> If your lens has an aperture actuating pin, or if its rear optical element extends beyond of the thread mount when focused to infinity, your camera will not be able to flip the mirror shutter - it will stuck against a lens elements.</p> <p>Solution is very simple: just add any M42x1 macro ring to your lens. We made this adapter as short as possible since many people using M42 focusing helicoids with it, and no any issues arise in such case. Adding a macro ring is very simple step for those who want to mount a lens to the adapter directly.</p> <p> </p>