From time to time I've seen Calumet and Orbit 8x10 cameras for sale. Calumets ar e called C1, C2, or C3. No one ever seems to talk about these cameras. How come they are not popular? They look very sturdy and rigid. Does any one know much ab out the differences between each of the three Calumet models and also the Orbit (I have noticed that the orbit and the C3 are painted black).