OK, thanks a lot. It's so heavy, I thought it might be for some kind of enlarger rather than a camera, but I wasn't sure. I know that Xenar means that the lens was produced as a taking lens, so I assumed that if it was an enlarger, it would be a Componon lens. Is there any difference between them? For example, are there any drawbacks to using this Xenar as an enlarging lens, and would an enlarging lens like a Componon work fine if I somehow mounted it for photographic use?