I have just received an antique plate studio camera which has a Ross 9 and a half inch Apo process Xpres f9 lens, number 159315. The camera is mounted on a large base and has to the rear, three differently sized opening doors, presumably for separately sized glass plates. To the rear also is a large heavy lens approximately 8" in diameter mounted on a metal swivel. I do not know if this lens was intended for checking the sharpness of the image or if it enabled the camera to double as a projector of slide images or whatever. Perhaps someone might have an idea. The camera is mounted on a large base which has small wheels underneath and a counter weight to stabilise the unit when it is in use.