In legacy camera mode: The projection plane and the device independent unit match with 2D ParallelCamera. Resizing the window will either see more or less of the scene. Objects in the scene will stay at the same size.
In the new camea mode: The eye position remain fix in the local coordinate of the camera. Resizing the window will deduce or enlarge the scene. The coverage of the scene remain the same, but objects in the scene will shrink or grow proportionally to the resized window.
We propose to rename the new camera mode as autoResize to imply the objects in the scene will automatically resize with the size of the window.