International projectionist (Jan-Dec 1953)

converging the lens axis to any desired plane, usually to a plane in front of the nearest object. Improper Camera Techniques Improper photographic techniques, usually wrong interaxial spacing (distance apart) of the camera lenses, results in "misinterpretation." This means observer confusion about spatial relationships, sizes of objects and shapes of persons. Deeper-than-normal scenes and strange forms of well-known objects conflict with the audience's experience. Proper interaxial spacing is calculated for the ultimate size of the projected picture. Example: a linear magnification of about 360 times is the determining factor for a standard 25 foot screen. Too large interaxial spacing will cause the picture to suffer from "miniaturization." Objects and people will look smaller than they should, and the depth of the scene will be abnormally increased in relation to the real spacing of objects. Too small interaxial spacing causes "giantism"; people and objects appear too large, and depth becomes drastically reduced. Mr. Norling discussed the features of all the cine-stereo cameras now in use; 3-D projection; dual images on one film; the anamorphoser lens system; the beam splitter; sequential frame projection; improved single-film systems; free-vision 3-D: the grid system; and the possibilities of stereoscopic motion pictures. In speaking of 3-D developments, Mr. Norling revealed that the "stereoscopic window" was not a necessity "if certain 3-D photographic and projection procedures are employed. It is perfectly possible to have 3-D pictures existing in space whose margins are vignetted, gradually shaded off from outer darkness to the full illumination of the picture itself. Some optical problems exist in the methods of doing this, but they are not very difficult to solve." The pioneer 3-D producer and designer of the cine-stereo camera bearing his name asserted: "Whatever the course of development of the 3-D art, one thing is certain: All the fundamental rules applying to proper photography and projection must be observed. Infraction of any one of these rules may set up visual disturbances ; may give the audience an unpleasant experience." Mr. Norling voiced his own opinion and that of the SMPTE when he concluded: "3-D cannot afford to break even one of the simple rules for producing and projecting good stereoscopic motion pictures." Those who are interested in a detailed description of several proposed methods of getting the two stereo images on one film should refer to the August, 1951, and February, 1952, issues of IP where Mr. Norling discusses the anamorphoser lens system, the beam splitter, sequential-frame projection, the grid system and various other methods of single-film stereo projection. 3-D As Viewed From Olympus DECENTLY in the know -all -and ■»yet-know-nothing citadel of culture known as Hollywood, Calif., there appeared before the Motion Picture Industry Council a Mr. M. L. Gunzberg, president of Natural Vision Corp., the sponsors of the process which is responsible for various 3-D Motion pictures now available in various theatres in the United States and elsewhere. Mr. Gunzberg, whose contributions to the technology of motion pictures have been widely publicized, seized the aforementioned occasion to divest himself of some rather extraordinary comment relative to the "principles" behind his Natural Vision process, including the reliance upon "convergence" rather than the "variable interocular" method used in "other 3-D systems." As reported in Motion Picture Herald (May 9 issue) Mr. Gunzberg's thought processes are as follows: "Normally, the eye doesn't stare straight ahead — as do the cameras in the variable inter-ocular method of shooting. In normal vision, the eyes converge on the subject that a person is looking at — and the area of vision is more or less concentrated. The cameras used in the Natural Vision method of shooting are set up so that they provide a natural convergence on the subject of greatest interest — just as the eye has a natural convergence. "To our knowledge, ours is the only 3-D system which has developed and emphasized 'convergence' and all the accompanying physiological and psychological factors." He recognized that there had been some complaints of eyestrain in connection with films utilizing the Natural Vision process, but contended they stemmed from inadequacies in projection or in unrecognized eye defects. On the whole, he declared, viewing properly photographed and projected 3-D films is excellent therapy for the eyes and adds to the general audience enjoyment of a motion picture. As to cries for "standardization," he pointed out that all 3-D films are projected on the same types of projectors, with reels of identical size — that complete standardization virtually exists as to films using the "stereo" method. A Commonplace of the Art Gunzberg's assertion that the Natural Vision 3-D cameras are the only ones that employ convergence is totally unfounded in fact. He further distorted the truth when he states that cameras employing variable interaxial shoot straight ahead and do not employ convergence. Actually, convergence as well as variable interaxial has been employed by Spottiswoode and Norling. Spottiswoode described his principles of convergence in the SMPTE Journal for October, 1952. Norling has upon numerous occasions described his employment of both convergence and interaxial spacing control, both of which he has used since 1936. Gunzberg's statement that his 3-D system is the only one that has developed an emphasizer convergence and all the accompanying physiological and psychological factors will come as a surprise to all those who have had any experience in cinesteregraphy. Eyestrain is Fact, Not Fancy Actually, complaints of eyestrain in connection with films utilizing the Natural Vision process is set up not only by inadequacies in projection but also in the faulty techniques notoriously used in the Hollywood "showoff" utilization of the 3-D process. See the statement by Dr. Leslie Knopp, president of the British Kinematograph Society, which appeared in the IP story anent the recent SMPTE convention (page 18, IP, May 1953). — James J. Finn INTERNATIONAL PROJECTIONIST June 1953