In the Parameter pane, a camera has several tabs that offer different camera properties:
View - This tab contains several parameters that are controlled by the camera handles and a few that are not. This is where you can set the render , which in turn sets the frustum's aspect ratio. You can override this value with a Render Operator.
You can also set the ratio for working with digital video and the for working with depth of field.
Cameras also have asetting for simulating realistic lens effects such as a fish eye lens. Note that this option will turn off micropolygon rendering in Mantra and should be used carefully.
Crop - These parameters let you focus on a smaller portion of the camera view. You can also rotate the camera around the line of sight.
Roto - This tab lets you set up a background clip for rotoscoping. An important tool when integrating live action and CG elements.