Stereo Photography
History
There were three major periods when stereo photography and stereoscopy was very much in fashion. The first one began in 1851, just 4 years after the invention of the stereo camera by Scottish physicist Sir David Brewster and Parisian Jules Dubosq. It began with the presentation of the invention to Queen Victoria at the Universal Exhibition of London in 1851. Of course professional photographers were dominating this first stereo photography period, using the early photographical processes like daguerreotype or calotype, but all one standard format: 85×170mm. Every better household had its own stereoscope for this format.
The second stereo photography era began at the turn from 19th to 20th century, when commercial stereo cameras, such as Jules Richard's Verascope or the Kodak Brownie Hawkeye Stereo (Models 1, 2, 3 and 4), were widely available. The third period started in the 1950s when the Stereo Realist brought on another boom of stereo cameras. A small resurrection occurred in the mid-1980s when Nimslo and Nashika cameras became available, offering lenticular printing to the general public. Currently, a smaller boom of stereo cameras is happening with new cameras being made, such as the 3D World TTL-120 medium format camera and the Horseman. Because of price, the new cameras are marketed mainly at a professional market rather than the hobbyist.
The main formats for stereo photography at the beginning of the 20th century were 6x13cm and 45×107mm for a pair of glass plate photos. In the 1950s the cameras tended to adopt some variation around the 24×23mm size per picture on regular 35mm film.
A timeless stereo slide format is the Viewmaster disc with seven stereoscopic pairs of 12.9×11.9mm slides. The slides are cut from developed 35mm slide film. The viewmaster camera uses the upper half of a film roll when it is advanced forward, and the lower half when the upper half is full and the film advance switched to backward. Thus 70 stereoscopic slide pairs can be made on one 36 exposure film roll.
Methods of Photography
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Stereo Camera
The easiest method is to use a stereo camera. Stereo cameras are made with two or more lenses, depending on the desired output. For most uses, only two lenses are needed. However, for lenticular printing (or use of an autostereosopic monitor), while two lenses can be used, three or more lenses are preferred in order to widen the angle of viewing. This is also one of the best methods for taking photos of objects in motion.
Some stereo cameras are made by joining two or more cameras together. RBT is an example of this type of camera.
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Cha-Cha
Cha-cha, also known as the astronaut shuffle, is the method of taking a photo, moving the camera to the right slightly, and then taking a second photo. The disadvantage of this is that this method is only good for non-moving objects, such as a landscape or architecture.
While this can be done freehand, a more precise way of taking a cha-cha photo is to use a slide bar, which will put the camera at exactly the place you need it to be.
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Twinning
Twinning is the act of placing two cameras side by side for the photo. This is usually a good alternative to cha-cha for digital stereo photographers, though it is a more expensive route. Twinning bars for various camera sizes are available that will place the lenses level and at the appropriate distance. Then, the cameras' shutters are released simultaneously by either manually pushing the shutter release on both cameras at the same time or, preferably, using a modified cable release that will sync the two cameras. This was sometimes done commercially - perhaps with very cheap cameras, for example Universal produced the Duovex - two $0.39c Univex Model A cameras fixed together.
Types of Stereo
Most stereo cameras will try to mimic the distance between the human eye. However, the human eye is insufficient for some photography.
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Macro Stereo
With a macro stereo, lenses are placed very close together in order to take a photo of very small subjects in stereo. With cha-cha, this can be achieved by moving the camera over only very slightly or rotating the object slightly. Macro stereo cameras have been made by RBT and David White Co.
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Hyperstereo
This method can only be done with cha-cha or twinning as the distance needed for a hyperstereo photo is much wider than a human eye. Hyperstereo is best for landscapes and cityscapes where a normal stereo photo would show absolutely no depth. Distance between two cameras depends on the subject. For example, doing a cityscape might only mean that you would need to take two photos on a roof with one camera at each end of the building, thus creating a lens separation of several feet.
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Lenticular Stereo
The Nimslo camera and special lenticular printing process was invented by Jerry Curtis Nims and Allen Kwok Wah Lo of Georgia, USA. Prior to the Nimslo’s release, there was much excitement surrounding it. The camera was to be “the third major advance in photography,” according to the Nimslo corporation, after roll film and Polaroid technology. Two years prior to the release, a prototype had been demonstrated in Cologne, Germany, at the Photokina exhibition, and shortly before Christmas 1982, the Sunday Times read: “The euphoria surrounding Nimslo’s 3D camera once again reaches fever pitch.” Unfortunately, the camera sales did not do as well as the company and its investors had hoped it would. An attempt was made to create a cheaper variant of the camera. The German camera designer Karl-Heinz Lange was involved in this development. Nimslo Corp was partly sold in the 1990s to Nishika, a Nevada company that acquired the Nimslo patents, continued the Nimslo as "Nishika 3-D N8000" and introduced a three lens stereo camera.
Viewing and Presentation Methods
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Stereo Cards
One of the oldest methods is a printed photo. These were very popular in the late 19th century up until the 1940s when View-Master became the popular format. For medium format photography, this method only requires a contact print.
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Stereo Slides
The most popular method, stereo slides are slides that are mounted in a stereo mount, such as a Realist-format mount or a View-Master reel.
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Anaglyph
Requires a pair of glasses, but can be viewed in print, on a monitor, or projected. Glasses in anaglyphs are usually tinted red and cyan, but red and green or red and blue are other options. This is the method that most people mistakenly associate with 3-D movies of 1953 (most movies produced in the 3-D movie boom of 1953 were polarized stereo). The disadvantage of anaglyphs is that the red tinting of the glasses gives many people eye strain or headaches after extended use.
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Lenticular Printing
This method is capable of free-viewing without the need for a viewer or glasses. In lenticular prints, multiple images are interlaced and then a plastic sheet is placed on top of the print. This is a popular method for movie posters, advertisements, and other areas where glasses or a viewer might not be desirable. Also frequently used to show simple animations.
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Projection
Projection is usually done by twining a pair of projectors or by using a stereo projector. The lenses of the projector are polarized so that when the polarized glasses are worn, they will give a very clear representation of the picture. However, a normal screen cannot be used. Only a silver screen is capable of the projection of stereo photography.
Polarization is the method currently used in digital 3-D movies as well as most stereo movies of the 1953 3-D boom.
As mentioned above, anaglyphs may also be projected.
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Autostereoscopic Monitors
Based on lenticular technology, this is a more recent development of viewing 3-D imagery without the need for glasses. Autostereoscopic monitors are still in their infancy, but improvements are coming all the time for improved viewing of 3-D viewing on a TV or computer without glasses. Autostereoscopic televisions are available up to 65".
A parallax barrier is a device to allow a liquid crystal display to show a stereoscopic image without the need for the viewer to wear 3D glasses. Placed in front of the normal LCD, it consists of a layer of material with a series of precision slits, allowing each eye to see a different set of pixels, so creating a sense of depth through parallax. A disadvantage of the technology is that the viewer must be positioned in a well defined spot to experience the 3D effect. In addition to films and computer games, the technique has found uses in areas such as molecular modelling and airport security. It is also being used for the navigation system in the 2009-model Range Rover, allowing the driver to view (for example) GPS directions, while a passenger watches a movie, and is rumoured to be used for the Nintendo 3DS hand-held game console.
