Cameras present a scene from a particular point of view. A camera is a non-rendered object in the scene. Cameras derive from the base class CameraObject. Developers writing camera plug-ins will usually derived from GenObject.
The viewport (ViewExp) can be associated with a camera using the method ViewExp::SetViewCamera(). To retrieve the camera's node from a viewport call ViewExp::GetViewCamera(). A viewport associated with a camera will return VIEW_CAMERA from the method ViewExp::GetViewType().