I have just found one of the above lenses for 50p, so I bought it out of curiosity. It is just a tiny lens in a barrel that is a push fit into a threaded brass outer mount. My guess is that it is a cine or projection lens. It is in good condition underneath all the dust. Does anyone know anything about the original purpose of this lens? Some variants seem to go for silly money, but those lenses are in mounts and may have stops or diaphragms. Has my 50p speculative investment paid off?