Oh, on the cameras.... All the perspective cameras (Carrara calls them "Conical") will exhibit "orbit" behavior if an object is selected. This can be very handy, especially in the model room. The Assembly Room cameras also can be set to Dolly camera. I personally find this more intuitive to set up a particular shot, and is probably more idiomatic for camera animations as well. However, it is notable that the control-key camera controls ALWAYS work in "normal" mode; although the trackball may control dolly-camera motions, you can't, alas, do the same with control keys. (Another thing I hope they change in the next version). Using magnification on any perspective camera is a Bad Thing. Within a few clicks your workspace view will start to look like a 1930's German silent film. The only option is, quite possibly, that "zero" you were asking about earlier; go to the camera drop-down in the upper left of the window, and navigate to "reset to default position." (Or whatever it is called...like I said, I'm trapped in a long render.)