I have a lens that I've used infrequently and I've just put it on a 5x7 studio camera to try some portraits. It has, very faintly printed, on its side, "Edison Manufacturing, Orange, NJ" and then, lower, Bausch and Lomb. The only thing listed in the Vade Mecum is this: "Edison" A brass and nickel projection Petzval type lens highlights the relation of Bausch & Lomb and the Edison Manufacturing Co, for whom this is a No1 type lens. It is probably about 3.5-4.0in." The brass and nickel projection part is right. Only problem is that this lens focuses on infinity at about 325mm and measures an f9 or 10 (WAG measuring system at work here.) My other Petzval lenses are quite rapid, more like f3.8 Any ideas?