International projectionist (Jan-Dec 1956)

FIG. 1 — The distortion problem inherent in wide-angle lenses is basically the same no matter what wide-screen process is used. Horizontal and vertical line distortions can be minimized if not eliminated entirely through careful camera placement with relation to the lines, or by choosing a location for the action having no clearly defined lines — as in the wide-angle panorama scene shown above. Wide-Angle Photography and Projection By GAYNE RESCHER, A.S.C. On the one hand, the wide-angle lens introduces distortions that later show up on the screen. On the other, it helps in obtaining the feeling of "participation" by the audience. This article appears here through the courtesy of the American Cinematographer. WHEN the screen opened up for first time on Cinerama's roller coaster a new era was born in motion pictures. Producers rushed their research departments to find ways of widening the standard screen, and today we are presenting all shapes and varieties of wide screens to the bewildered but interested public. Somewhere along the line, however, we may have forgotten what started all this; we may have lost sight of the quality of wide screen that first intrigued us. The Cinerama roller coaster sequence owed its effect not so much to the width or curvature of the screen as to the extreme wide angle with which it was photographed. The feeling of participation — which is really the only added dimension of Cinerama — is there only when wide-screen is combined with wide-angle and with movement. And yet the use of the wide angle lens with the various wide screen processes has been discouraged — in many cases by the very studios that developed the process — because of the problems of distortion. Some studios, after a few unfortunate experiences, have recommended that no wide lenses be used for widescreen photography. But this policy deprives them of one of the main advantages of wide-screen — putting the audience into the action. Cause of Distortion The distortion problem is basically of the same nature no matter what wide-screen process we are dealing with. It depends mainly on the angle of field covered by the lens. Obviously, the wider the angle of field, the greater the distortion. While the problem is basically the same, there are variations with each process which I will not attempt to cover here. My purpose is to show the nature of these distortions rather than describe them in detail. We are therefore assuming in the following discussion that the projection setup is such that the projectors are level with the screen (as in Cinerama) and that no corrections have been made during printing. (As is possible with Todd-AO). Let us assume that we are photographing a set of straight horizontal lines with an extreme wide-angle lens. When projected, the center line will be the only line that remains straight. Lines below the center will bend upward as they approach the edge of the screen while lines that are above center will bend down in a similar manner. This bend becomes more pronounced the closer we get to the top and bottom of the screen. (See Fig. 3). When thinking in depth we might say these lines bend back into the screen. Now while this is a basic distortion, the straight line running through the 16 INTERNATIONAL PROJECTIONIST JULY 1956