Cinema: HOW REAL CAN MOVIES BE?

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Movies try to "can" dramatic events and dish them out later for distant audiences. They can never be perfect reproductions of reality, but the margin between the original scene and the projected one has narrowed step by step. The new devices—3-D, wide screen, stereophonic sound—are further steps toward reality.

The early movies showed light and shade. Human eyes see a great deal more: they are sensitive to color, and are also rangefinders. When both eyes look at the same object, they "toe in" slightly. The brain measures the converging angle, and from it, estimates the object's distance.

The movies first got excited about color in the early 1930s, but the single camera, projecting a single picture, lacked binocular vision. It saw the scene as a one-eyed man sees.

Binocular Cameras. Two camera lenses can approximate the two human eyes. They take two pictures of the scene from slightly different angles. Both pictures are thrown on the same screen, and the viewers are given means of seeing only one of them with each eye. The trick is worked with polarized light.

Ordinary light vibrates transversely (like shaking a rope) in all directions, but if it is passed through a Polaroid filter, it emerges with nearly all of its waves vibrating in the same direction. The two films exposed by the cameras are thrown on the same screen by two projectors. In front of one projector is a Polaroid filter that passes light with its waves vibrating, for example, vertically. In front of the other is a filter that passes light with horizontal vibrations. The viewers get glasses with lenses of Polaroid plastic. One lens passes light from the screen that is polarized vertically. The other passes light polarized horizontally. Thus each eye sees only one of the pictures. Since each eye sees the scene from a slightly different angle, as in natural binocular vision, objects appear to have definite distance.

Beyond the annoyance of glasses, this kind of 3-D has many faults, some of them incurable. Objects on the screen look solid, all right, but unless a viewer sits in a favorable part of the theater, they are distorted —either flattened or pulled out toward him. A certain amount of eye-strain appears almost inevitable.

Peripheral Vision. Besides binocular vision, human eyes have another ability that conventional movies lack: they see a much wider field. A man with normal vision can see about 200°, while the ordinary movie camera sees 35°. Actually, the eyes see most of their field in a vague way. Only the center is sharp and detailed. The purpose of "peripheral vision" (the rest of the field) is to tell the eyes what to look at. When some interesting object appears "in the corner of the eye," a quick movement shifts it to the center of vision. In conventional movies, there is no corner of the eye. The camera swings to each object of interest and brings it to the center of the screen.