Which camera is ideal
There are two types of custom cameras that you can create: Linear and Orbit.
Linear Camera
A Linear Camera always travels in straight line without
considering its own angle.
Therefore, when it is used to orbit and shoot a target object, the result can be odd.
However, you are free to edit the transform curves of the Linear camera in the Curve Editor.
Orbit Camera
An Orbit Camera, on the other hand, moves in a curved pattern
according to it's orientation.
Therefore, the shot is more ideal when it orbits a target object.
However, you can not adjust the transform data of the Orbit Camera in the Curve Editor.