When you look at your scene in Maya, you are looking through a camera. Think of it as being a director on a movie set and looking through a camera lens. Your field of view is restricted to what you can see through that lens.
By default, Maya has four cameras that let you view your scene in a panel: the perspective camera and the three orthographic cameras (side, top, front) that correspond to the default scene views. You look through these cameras (panels) as you model, animate, shade, and texture objects.
Typically, you don’t use these default cameras to render a scene; you create one or more perspective cameras from which to render. The only difference between a rendering camera and any other camera through which you can view your scene is a flag that allows it to render the scene.
For more information on the kind of cameras you can create, see Maya camera types.