The international photographer (Jan-Dec 1935)

January, 1935 The INTERNATIONAL PHOTOGRAPHER Twenty-seven effect, particularly the memory chambers. ( It has been shown that people not endowed with a well developed perception of stereoscopy have faulty memory. ) Up to the present time, the functions of the rods and cones and the Muller fibres of the eye and the optic tract, and the neurons connecting the retina to the brain, have been imperfectly understood. Delmar A. Whitson advances a theory that insinuates the subject into the everbroadening realm of radio, by observing, in the construction and association of the rods and cones, a system that suggests an electronic relation, to form a sort of receiving set. According to physical laws, any instrument capable of receiving a wave also has the power of emission. Curiously enough, this theory appears to be substantiated by a series of experiments conducted by Dr. Charles Russ, by which he caused a delicately balanced electrical instrument to respond, actively, to the direct glance of the eye. Whitson's theory provides the assumption tli.it the effect of vision is the result of a heterodyne action produced by the waves of the eye challenging those directed towards the eye. It has been established that in both sound and radio waves the heterodyne sets up a long beat note and that this beat wave may be responsible for the effect of vision. This does not seem to conflict with the accepted theory of light for we know that the eye is not constructed to receive the full rays of the spectrum. This theory might suggest that stereoscopy is the result of a very complex system of radiation from near and remote planes, limited in monocular vision and multiplied in binocular vision, and, in fact, the more complex the radiation, the more pronounced the effect of stereoscopy. It might also agree with the observation that perception of stereoscopy varies in individuals, due to the individual pathological condition and arrangement of the rods and cones. And, further, the idea of the eye emitting a wave agrees with the simplest explanation of the operation of the brain, "which is, in its highest activity, the organ of consciousness or mind, and its general function is that of furnishing the most complex and extensive outgoing stimulation of muscles and other active tissues as a response, more or less immediate, to the most complex and extensive incoming sensory stimulation." The psycho-physiological consideration has so engrossed some stereo enthusiasts that it has been hinted that some progress has been made in attacking the problem from this angle. But, unfortunately, we have been furnished no details by which we may judge the merits of such a conception. However, the more conservative students reflect the attitude of the aforementioned Dr. Russ, "supremely skeptical of any matters that do not lie within the scope of material proof, to be shown by touch, sight and measurement." This present consideration revolves around the socalled pseudo effect, which has puzzled so many observers, and we revert to it as a concluding idea. As to the da Vinci effect, of viewing a picture with one eye, we believe that this is merely a matter of psychosis, in finding a perfect adjustment of the perspective "point of sight ;" but we contend that there is no such effect as pseudo stereoscopy as regards vision, and that even in monocular vision, the effect is complete but is limited to the degree of parallax to which the single eye is capable of producing ; and that the effect is enhanced or multiplied, in the use of both eyes by obtusing the triangulation. In viewing, with one eye, a group of small objects at very close range, we experience a perfect sense of third dimensional displacement, and that the effect is reduced as we remove the group from the eye. Likewise, in viewing objects at a great distance with both eyes, the field flattens in proportion to the distance of the objects from the eye. In single eye vision, at very close range, the principle that every point of a lens is an individual lens, with the iris providing a minute inter-pupilary distance, a very complex system of triangulation is set up. However, this is only noticeable at an extremely short focus, and it is probably for this reason that it has been overlooked as an important factor in the study of stereoscopy. In the present subject, the field of physics is so greatly influenced by the physiological consideration that it is almost impossible to deduce it to principles or rules, and that an attempt to do so merely becomes a further elaboration. As briefly as possible, therefore, we define stereoscopy as photo-triangulation registered in the brain through the medium of the optic nerves. The spread of the image on the retina forming the base of the triangle and the diameter of the iris forming the numerous points of parallax and the degree of the effect varying with the focal length and the distance of the objects. The rods and cones of the eyes are supposed to function dextrally and sinistrally and that the simultaneous registration of their activity produces the highest degree of stereoscopy, but it is also believed that the optic nerve system is so complicated and sympathetic that even in a one-eye exposure a certain number of the rods and cones effect a cross nerve stimulus to the opposite set of centres, especially near the periphery of the retina, which permits of a considerable degree of photo-triangulation in the single eye. This cross nerve effect is feeble and limited, in individuals, to the degree of this peripherical stimulus. It must be understood that this effect is observed at very close range and with the aid of an auxilliatv lens to help adjust the focus, for although the eye contains an adjustable lens it has its limits, even in extremely myopic vision. In conclusion, we can only center our hopes in the fact that nature generously provides many means to an end, that necessity frequently solves her problems. Publicdemand prodding a bright research mind, with unlimited laboratory facilities and generously endowed may solve the problem. We assume that this problem excludes the use of optical devices bv the audience. On behalf of many cameramen who have reason to be grateful to them for courtesies extended, THE INTERNATIONAL PHOTOGRAPHER wishes the Motion Picture Relief Fund Executives the Happiest and Most Prosperous of New Years — Francis X. Baur, Miss Vilma Basher, Miss Florence Homan, and Mrs. Adele Macomber. Please mention The International Photographer when corresponding with advertisers.