In the simplest instance the cinematic apparatus purports to set before the eye and ear realistic images and sounds.
This effect is ideological because it is a reproduced reality and the cinematic experience affects the viewer on a deep level.
He relates the similarities of being in a darkened room, having someone else control your actions/what you do, and the inactivity and passivity of the two activities.
He goes on to say that because movie-goers are not distracted by outside light, noise, etc., due to the nature of a movie theater, they are able to experience the film as if it were reality and they were experiencing the events themselves.
Apparatus theory also argues that cinema maintains the dominant ideology of the culture within the viewer.