The BPM bellows system around in the 70s was a versatile system with mounts to accommodate most camera and lens fittings. But it wasn’t the only one. The likes of Soligor, Hama, Russian, Kenlock and others made similar interchangeable systems, but with their own system of mounts. Im not sure which are interchangeable between bellows makers, but maybe the anatomy of a BPM mount may help you find out if the bellows you have can be used with a BPM mount.
