There are many different ways a film is shot and then composed for theaters and home video. The open-matte example is above. There's anamorphic films which use special lenses to squeeze a wide image (2.35:1 mostly) onto 35mm film. When these films are transferred to full screen, roughly 40% of the image needs to be cropped off because there is no additional information on the film to open up for 1.33:1. Examples of these include the OT Star Wars films, Jaws, all of the Indiana Jones films, Die Hard, Pulp Fiction. There's Super 35 which is a process of shooting on 35mm film with no optical soundtrack which gives a 1.33:1 negative. For theatrical exhibition, a 2.35:1 image is composed from this 1.33:1 negative. When the film goes to video for full screen, the unused portion can be opened up to fill the screen like in the Spies Like Us example, but usually it's a combination of cropping and opening up the frame. Also, often special effects shots are done hard matted in the camera to the theatrical AR or close. Those scenes would need to be subject to the same cropping processes as anamorphic films. Examples of Super 35 films are Terminator 2, Titanic, and the Lord of the Rings trilogy. There is also 3-perf Super 35 that is ofter used which has a 1.78:1 native aspect ratio, for a standard television set, that would be subject to cropping, but not as severely as an anamorphic film. The last major film process these days is digital. There's no film involved, but the native AR for those films are usually 1.78:1