This camera node provides a perspective view, like a regular camera. This is the 'standard' camera type that you will probably use most often. In addition to a normal perspective, this camera type also provides controls for the depth of field, and the focal length of the camera, as well as controls, to do with the aperture of the camera. This allows various camera lens effects, including bokeh, to be simulated.
The camera page has more details about the controls.