Well, I acquired this lens together with some others, and it looked interesting. Does anyone have ANY information on it at all? I can't seem to even find a reference to any large lenses by Ernemann at all! Let alone past eBay auctions or any way to find a value. It is very heavy, has a metal barrel covered with leather the length of it's focal length, with a really fine focusing mechanism. Fine as in, really really long throw. When you focus, you can actually see the ridges on the helicoid mechanism, and the whole front turns. The aperture is changed by two 'ears' at the front of the lens. It has a large tripod screw in the middle, and a screwmount at the end for the body. It's not M42, M39. It is smaller then M42 though, but larger then M39. It has two serial numbers, one is no. 52841, but the other is no. 8. Perhaps the longer serial is a continious serial, and the 8 is the serial of this type of lens? It would certainly explain the lack of information. I'll be sure to post photographs later on. With kind regards, Mathijs.