Movie Makers (Jan-Dec 1952)

108 Photographs by Crocker Films FIG. 1: A shutter speed of 1/480 of a second was achieved on the Cine Special by shooting at 64 frames per second with shutter only Va open. FIG. 2: By holding his camera on its side, the author changed the long frame dimension to a vertical for maximum image room of dancing figure. TRY ACTION STILLS WITH YOUR MOVIE CAMERA! BENJAMIN B. CROCKER, ACL FOR some time now I have felt that there is something wrong, radically wrong, with the usual technique of taking fast-action stills. To be sure, still cameras today are equipped with shutters of dazzling speed — 1/1000 of a second and less, which is certainly sufficient to stop the swiftest action. The trouble is that the photographer himself has not kept pace. To begin with, his eyes cannot respond to more than sixteen impressions a second. (This is probably just as well, or movies and TV would be impossible.) Nor is the eye the only factor. The limited speed of nerve impulses, muscle contraction and shutter mechanisms introduce further delays between the instant that the perfect scene is observed and the instant at which the picture is taken. A skillful photographer can learn to guess when a good pose is about to occur and shoot beforehand. The fact remains, however, that he is only guessing as to the excellence of a pose not yet in existence. And by the time the pose does exist, it will be impossible for him to act quickly enough to photograph it. In short, action photography with a still camera seems largely a combination of guesswork and luck, and the factor of luck is almost always bad. The obvious solution to this problem, of course, is to use a high-speed camera taking many pictures a second, which can be examined later in order to determine the most perfect instant of the action. The only device which meets this specification is a movie camera of some sort. But the extreme enlargement that would be necessary to obtain a still of reasonable size from a 16mm. camera would seem to rule out the idea completely as far as the amateur is concerned. A little simple mathematics, however, tells an encourag ing story. A 16mm. frame is 10.41 millimeters wide. The resolving power of a typical, fine-grained reversal film is 90 lines per millimeter, a value which easily can be exceeded by a really good lens. The maximum detail obtainable with a 16mm. camera is therefore approximately: 10.41 x 90 = 940 lines The resolving power of a high quality halftone engraving screen, such as is used by Movie Makers, is 120 lines per inch. Thus to represent 940 lines, a 120 halftone cut would have to be: 940 120 7. mes 1 ong What this last equation means is that if the full width of a 16mm. frame is enlarged and printed as a 120 halftone cut 7.8 inches long, it will be just as clear as a cut 7.8 inches long made with an 8 by 10 inch view camera. (That is, provided a truly high grade lens is used with fine grained film and also provided that there is no loss of detail on enlargement.) In practice, of course, one cannot quite equal such perfection. For one thing, it is almost always necessary to crop the original field, at least slightly. For another thing, the process of enlargement will generally result in some loss of detail. But with care, it should be possible to obtain a 4 by 6 inch halftone cut from a 16mm. photograph that no photographer in the world could tell from a 4 by 6 halftone made from a large-camera picture. Of course, if the two photographs were compared closely, one could spot the fine details that would identify the picture taken with the larger camera. But in the cuts the extra detail would be invisible, since it would be smaller than the halftone dots themselves. Since halftone definition is adequate at normal viewing distances, this