Hello, I have and love a 6 1/2 X 8 1/2 Rochester optical Reversible Back Premo camera. It has a very small lens board which measures 3.5"x3.5" I am looking for a vintage soft focus lens in a portrait focal length which will fit on a board this small. I have not been able to come up with anything that will work. I had an English half-plate petzval which fit but the focal length is just too short. I do not need a petzval lens although it would be great. I could be happy with a Wollensak Velostigmat Series II 4.5 if I could figure out a way to mount it on the camera. This particular camera is such a joy to use. It has been my favorite vintage view camera to date. Thanks in advance for your suggestions.