I've recently bought a Lancaster Instantograph 1887 model, 1/2 plate size, my first XIX Century dry plate camera. In fact I bought this camera because it came with a full set of 3 double book-type holders and three brass lenses. So I thought it was a wonderful complete set. But the lenses are dissapointing. Two of them are of a larger diameter than the one in the camera (one is a Goerz, the other only says "Excellent"); and the only one that fits in the camera's thread is of the Waterhouse stops type, but without it's stops. So I can't use it except at full aperture.

What I'm planning is to buy a lens with the proper diameter thread (37mm / 1,45in. more or less) and it has to be a Lancaster set to be able to use it with a wonderful Lancaster rotary or see-saw shutter. The problem I have is that most lenses I have seen seem quite larger. Anyone knows if this kind of mounting has some special name or type of lenses? There's some kind of standard sizes in lens diameters of this era, like the plate sizes?

Thanks in advance