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1953-54 Theatre Catalog, 11th Edition, Page 253 (217)

1953-54 Theatre Catalog, 11th Edition
1953-54 Theatre Catalog
1953-54 Theatre Catalog, 11th Edition, Page 253
Page 253

1953-54 Theatre Catalog, 11th Edition, Page 253

portraits and novel lens-holding viewers. It is mounted in a handsome case, provided with a viewer containing a pair of convex lenses, with centers spaced two and one-half inches apart. The pictures, peculiarly enough, are spaced only two inches apart, introducing a little difficulty in viewing, but fusion can be attained. The name of this device is nMacheris Improved Stereoscope," patented March 8, 1953. It was made in Philadelphia.

Unfortunately, many stereoscopes had tie-ve-strain" as a builtsin feature. Many stereograms were poor in definition and contrast, and sloppily mounted. These faults, working together, probably was one reason for the loss of popularity of the stereoscope.

Amateurs who still kept alive their interest in stereoscopy had to perform a number of operations not required in ordinary photography, such as the transposition and mounting of the pair of pictures. These requirements made many give up the pursuit of the art.

Oliver Wendell Holmes called a photograp ha mirror with a memory? and it was this pioneer in the art who Chris tened the stereoscopic picture "sun sculpture." The "sculpture" in a stereogram is tenaciously remembered and details are retained that are soon forgotten in a ftfiat" picture.

Binocular Vision

The sensations received by the eyes are transmitted to the brain where, in a psychic assembly room, the two disparate images are fused together, so that we become conscious of relief in the view. But fusion cannot be accomplished without strain unless the two images are of exactly the same size and the ffpicture" axes aim at. the same points. Inability to fuse exists in an eye disorder called ftdiplopiai'i in which double images are seen, and in fianesikonia," the term applied when the eyes form images of different sizes or shapes.

The Stereo Still Camera

A stereoscopic camera not having matched lenses can be said to have itanesikonia," as can projectors with unmatched lenses. If the images on the screen do not align properly, the projector has "diplopia," and the observers eyes will have to perform acrobatic feats to attain fusion, and in the process, will suffer strain. Veracity in a stereogram exists only if it is taken properly.

Stereoscopic cameras were made in scores of styles throughout the past hundred years. Among the most widely used American stereoscopic cameras was the Stereo Graphic with a focal plane shut< for. It took the stereoscopic pair on a five inch by seven inch plate.

The Europeans, principally the French and the Germans, have been very active in stereoscopy and have produced a wide range of cameras and other stereoscopic devices. A well-designed French camera was the Richard Vcrascopc, which accommodated both plates and roll films. Separate magazines were furnished for each. Verascopvs were also made in six by 12% cm and 45 by 107 mm sizes. A single guillotine-typo shutter operates between the elements of their two lenses. Shutter speeds up to 1/120 of a second were provided.



Other similar European cameras made pictures a good deal smaller than the original Richard, but some made pictures as large as three and one-half inches horizontal and four and one-half inches vertical. The German Ica contained a valuable feature usually overlooked by makers of stereoscopic cameras. This was a provision for changing the lens spacing for principal objects at different distances. The Icafs lenses move toward each other, reducing the lens interaxial when focusing on a near object, and spread farther apart when focusing on a far object. This is a feature of great importance and is discussed later in some detail. Probably, other stereo camera makers will some day make devices to provide the highly useful and often necessary varying interaxial. If it were built into the camera, there would be no necessity for using smaller slide masks that cut down the sides of the image to attain satisfactory viewing, as we find recommended practice for close ups made by many modern cameras.

AROUND THE MIDDLE of the last century there appeared a number of viewers for viewing paper stereograms. A great many of these viewers were often in elaborate cabinets as can be seen here.

Undoubtedly, the camera most responsible for the resurrection of interest in the three-dimensional art is the Stereo Realist. This camera was the first in the modern development of the stereo art which has features that appeal to amateur photographers, particularly those who have been making color transparencies on 35mm film. Like most popular itsingle-eye" miniature cameras, the Realist has coupled range-finder focusing, easy-to-learn controls and in contrast with earlier cumbersome cameras, it fits the hand.

"Slide Board" for Stereo Still Lifes

A single lens camera can be used to make stereoscopic pictures of still life subjects by mounting one camera on a uslide board." Because only a single lens is used, both images will be of exactly the same size, and there will be none of the faults contributed by a pair of unmatched lenses. The slide board may be a simple one made of wood, but the precision provided by metal construction is much to be preferred. Slide boards can be made as long as desired, but there is

ONE OF THE EARLIEST stereoscopic devices is the daquerrofype with lens stereoscopic.

little use for one that permits a camera shift of more than three or four inches, except for very special purposes.

With a slide board, closeup stereograms can be made of objects so small and so enlarged, that the interaxial spacing may be only a few millimeters. The slide board enormously extends the range of effects offered by stereoscopic photography, and it is an economical and convenient method for the person who would like to start in stereoscopy without first buying a two-lens camera.

Kennedy Stereo Camera

Even without a slide board, the single lens, if its aperture is large enough, can be employed to produce stereograms of excellent quality. Its usefulness seems to fall only in the still-life field, since the effective aperture employed for each image is of a rather low order. The system is simplicity itself, and was designed and built by Professor Clarence Kennedy of Smith College, in cooperation with Dr. Edwin H. Land and Otto E. Wolff. Professor Kennedy had employed it principally to obtain large stereograms of sculptures. Its diagrammatic representation shows that only a part of each lens is used for forming each member of the stereoscopic pair. If the lens has a large enough diameter to accommodate the desired result, the two individual lens "stops" can be separated to the required spacing called for by the geometry of the stereogramis planned use. A lens of large diameter, 75mm or more, must be used. Its focal length is determined by the type of stereograms to be made. A large diam SEEN HERE ARE two stereoscopic cameras. On the left is :1 Stereo Graphic, and the right an Ica.

1953-54 Theatre Catalog, 11th Edition, Page 253