"Elgenper" Would it really have that iris diaphragm if intended for high- resolution copy work of flat subjects? As wide as possible (and corrected for that) is the usual recipe for max resolution, just like astronomical optics. Yup.. all of the copy cameras I've come across have had lenses with irises - the agfa repromaster I last stripped had a 150mm, a G-Claron 210mm and a 270mm (all Rodenstock ) - and again, all had irises. OTOH, the absence of a shutter hints that exposure was regulated by controlled lighting instead (or manually with a lenscap for a really old lens, or a pinhole). repro camera lighting was in the later models often controlled with a timer - the last one I owned had an onboard densitometer and a coupled lightmeter for autoexposure (!) - it even had an auto magnification setup - you punched in the mag you wanted, it rotated the lens barrel to pick the appropriate lens, raised/lowered both the stage and the bellows then you hit 'go' and it autoexposed the image. really sophisticated stuff.. One of the reasons copy cameras had irises was to control DOF for, believe it or not, quite a bit of photography of 3D objects was done under these things. karl
