Stereo photography techniques

Stereo photography techniques are methods to produce stereoscopic images, videos and films. This is done with a variety of equipment including special built stereo cameras, single cameras with or without special attachments, and paired cameras. This involves traditional film cameras as well as, tape and modern digital cameras. A number of specialized techniques are employed to produce different kinds of stereo images.

It is necessary to take two photographs from different horizontal positions to get a true stereoscopic image pair. This can be done with two separate side-by-side cameras; with one camera moved from one position to another between exposures; with one camera and a single exposure by means of an attached mirror or prism arrangement that presents a stereoscopic image pair to the camera lens; or with a stereo camera incorporating two or more side-by-side lenses.

Charles Wheatstone first began experimenting with stereopsis in 1838 using specially constructed drawings. The invention of photography in 1839 opened up a new and more detailed medium for his experiments and the first photographic stereoscopic pairs appeared in the early 1840s as Daguerreotypes and Calotypes. By the 1850s, a stereoscope and an assortment of professionally photographed stereo views were becoming part of the standard equipment of a properly furnished middle-class parlor. In the 1890s, photographic plates and films sensitive enough to make casual "snapshot" photography practical were available, and combined with easy-to-use cameras they were making amateur photography a very popular hobby. Stereo cameras were in the mix. The earliest were inconveniently large and the result was a pair of paper prints mounted on a card for viewing in a standard stereoscope. They were soon joined by smaller cameras that yielded relatively small stereo slides on glass. The popularity of stereo photography declined after the First World War and plummeted during the Great Depression of the 1930s.

In the late 1940s, compact imported European stereo cameras that used 35 mm slide film began appearing in the US market. The most notable example was the Verascope F40. These cameras featured a "7P" format, meaning that each image was 7 film perforations (sprocket holes) wide, yielding 11 stereo pairs on a 20-exposure roll of 35 mm film. Because these cameras (and some later models) came from Europe, this became known as the "European format".

In 1945, ads began appearing for an American camera known as the Stereo Realist. The camera was not actually available for purchase until 1947, but the ads generated a lot of excitement among stereo photography enthusiasts. The Stereo Realist featured a more compact 5P format, which soon became known as the "Realist format". It yielded 16 pairs on a 20-exposure roll and was therefore more economical than the 7P format. By 1952 several competitors were already marketing their own cameras using the 5P format, making it the de facto US industry standard. Several 5P format cameras were also made in Europe.

More compact and convenient than their pre-World War II predecessors, these cameras adopted the increasingly popular 135 film (35 mm) format that allowed the use of Kodachrome color film, which produced color transparencies ("slides") instead of prints on paper. The relative novelty of Kodachrome's vivid colors and the realism of 3-D were each attractive individually, but the astonishingly lifelike effect of the two combined proved irresistible to many consumers.

The new cameras were marketed with corresponding two-lensed Realist-format slide viewers, which typically had a built-in light source and adjustable optics. With only these two items the owner could capture, relive and share multicolored and stereoscopically preserved memories. For group viewing, a polarized stereoscopic slide projector, silverscreen, and polarized glasses could be added to the system. Other accessories were available, including equipment and supplies for those who preferred to mount their own slides. Both Realist Inc. and Kodak offered stereo mounting services for those who would rather not.

The popularity of amateur stereoscopic photography helped trigger a brief pop culture fad of 3D movies, 3D comic books, etc., which in turn helped to introduce new enthusiasts to the ranks of amateur stereo photographers. Unlike the pop culture 3D fad, which came and went quickly and was primarily a 1953 phenomenon, the popularity of amateur stereo photography started earlier, grew more slowly, peaked later, and declined more gradually. Eight new stereo cameras hit the market in 1954, including the Kodak Stereo Camera which may have driven several competitors out of the business. Kodak's stereo camera was not discontinued until 1959, Kodaslide stereo viewers were available until 1962, and the Realist continued in production, although ultimately in very small quantities, into 1971. Subsequent decades found new users replenishing the ranks of loyal devotees and supporting a solid market for second-hand equipment. Kodak's stereo mounting service was continued, through Qualex, into the early 1990s. Even today, despite the general transition from film to digital and from slide viewing and projection to slide scanning and video display, some of this sturdy equipment is still in use by a small core of enthusiasts of all ages.