This likely is a Petzval, but it's not a projection lens. Note that it has a slot for Waterhouse stops. I think it's missing it's lens hood. If you unscrew the front lens group it should be a cement doublet (2 lenses joined together.) The rear should be two single elements with a space between them. If the rear element looks like the front ones, then this is a rapid rectilinear lens. I'm going to take a guess that this lens covers quarter plate.


Kent in SD