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or for ordinary purposes. These effects can be an obstacle or an asset and the cameraman should be aware of them so that he can use them to the best advantage.

Focusing

The three lens optical system of the Cinerama camera is such that it is difficult to have match-lines which are perfect at all distances from the camera. The camera is so designed that the point of best match is at that distance at which the camera is critically focused. If the subject is on the match-line the camera should be focused on that subject if good overlap is to be expected or desired. Objects closer to the camera than that have a tendency to become broadened or enlarged, while objects farther away overlap and disappear. For example, it is possible for a complete letter in a sign in the background to completely disappear when that letter is on the match-line and the camera is focused at a point close to the camera. On the other hand it is possible for a person's face, if it is on the match-line close to the camera, to be broadened to grotesque proportions when the camera is focused on a distant object, even to the extent that the person might appear to have two noses or three eyes.

Action too will be distorted if it takes place on the match-line unless the camera is focused for that action. A person