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.
Types of photography
Film photography
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.Make Your Own Stereo Pictures by Julius B. Kaiser, pp. 41-43. 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.Amazing 3D by Hal Morgan and Dan Symmes, pp. 32-33. 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.Make Your Own Stereo Pictures by Julius B. Kaiser, p. 42. By 1952 several competitors were already marketing their own cameras using the 5P format, making it the de facto US industry standard.Amazing 3D by Hal Morgan and Dan Symmes, p. 42. 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.,Amazing 3D by Hal Morgan and Dan Symmes, pp. 44-45. 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.Amazing 3D by Hal Morgan and Dan Symmes, p. 49. 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.
The 1980s saw a minor revival of stereoscopic photography when several point-and-shoot stereo cameras were introduced. Most of these cameras suffered from poor optics and plastic construction and were designed to produce lenticular prints, a format which never gained wide acceptance, so they never gained the popularity of the 1950s stereo cameras.
In the 1990s, cameras came out that were intended to make stereo pairs, specifically designed to use print film, producing a half-frame format that could be viewed using freevision or the included print viewer, directly as it came from a standard processing lab. The original Loreo was the pioneer,Stereo World, Vol. 17 #4, September/October 1990, pp. 28-30. but it was followed by several other cameras, including some designed to take macro shots.
Digital photography
The beginning of the 21st century marked the coming of the age of digital photography. Stereo lenses were introduced which could turn an ordinary film camera into a stereo camera by using a special double lens to take two images and direct them through a single lens to capture them side by side on the film. These are also available for digital SLR cameras.
It is also possible to create a twin camera rig, together with a "shepherd" device to synchronize the shutter and flash of the two cameras. By mounting two cameras on a bracket, spaced a bit, with a mechanism to make both take pictures at the same time.
In 2009 digital stereo cameras such as the Fuji W1 began appearing in the consumer market. Several companies joined the digital stereo market, producing digital stereo cameras that sold for as little as $100. 3D capability was even added to some smartphones.
Newer cameras, such as the Fuji W3, can also be used to shoot full motion 480P video at up 30 frames per second or 720p video at 24 frames per second, thus making amateur 3D video possible. Some cameras can also take images that greatly exceed HDTV resolution at up to ten pictures per second.
If anything is in motion within the field of view, it is necessary to take both images at once, either through use of a specialized two-lens camera or by using two identical cameras operated as close as possible to the same moment.
A single camera can also be used if the subject remains perfectly still (such as an object in a museum display). Two exposures are required. The camera can be moved on a sliding bar for offset, or with practice, the photographer can simply shift the camera while holding it straight and level. This method of taking stereo photos is sometimes referred to as the "Cha-Cha" or "Rock and Roll" method. It is also sometimes referred to as the "astronaut shuffle" because it was used to take stereo pictures on the surface of the Moon using normal monoscopic equipment.Stereo World, Vol. 17 #3, National Stereoscopic Association, pp. 4–10.
Digital stereo bases (baselines)
There are different cameras with different stereo bases (distances between the two camera lenses) in the nonprofessional market of 3D digital cameras used for stills and video:
? mm Inlife-Handnet HDC-810 10 mm Panasonic 3D Lumix H-FT012 lens (for the GH2, GF2, GF3, GF5, GF6 cams and also for the hybrid W8 cam). 12 mm DXG-5D8 cam and the clones Medion 3D and Praktica DMMC-3D. 15 mm Ararat Macro Beam Splitter for smartphones. 20 mm Sony Bloggie 3D (MHS-FS3). 23 mm Loreo 3D Macro lens. 25 mm LG Optimus 3D, LG Optimus 3D MAX (smartphones) and the Cyclopital3D close-up macro adapter (for the W1 and W3 Fujifilm cams). 28 mm Sharp Aquos SH80F and SHI12 (smartphones) and the Toshiba Camileo z100 camcorder. 30 mm Panasonic 3D1 camera. 32 mm HTC EVO 3D smartphone. 35 mm JVC TD1, DXG-5G2V, VTech Kidizoom 3D, GoPro HD Hero kit 3D, Nintendo 3D, Vivitar 790 HD (only for anaglyph stills and video), and AEE 3D Magicam. 40 mm Aiptek I2 (also the Viewsonic clone), Aiptek I2P Aiptek IS2 and Aiptek IH3 3D cams. 50 mm Loreo for full frame or non digital cams, and the 3D FUN cam of 3dInlife (also the clones Phenix PHC1, Phenix SDC821 and Rollei Powerflex 3D). 55 mm SVP dc-3D-80 cam (parallel & anaglyph, stills & video). 60 mm Vivitar 3D cam (only for anaglyph pictures). 65 mm Takara Tomy 3D ShotCam. 65 mm Kandao QooCam EGO 3D Camera. 75 mm Fujifilm W3 cam. 77 mm Fujifilm W1 cam. 88 mm Loreo 3D lens for digital cams. 140mm Cyclopital3D base extender for the JVC TD1 and Sony TD10. 200mm Cyclopital3D base extender for the Panasonic AG-3DA1. 225mm Cyclopital3D base extender for the Fujifilm W1 and W3 cams.
Base line selection
For general purpose stereo photography, where the goal is to duplicate natural human vision and give a visual impression as close as possible to actually being there, the correct baseline (distance between where the right and left images are taken) would be the same as the distance between the eyes. When images taken with such a baseline are viewed using a viewing method that duplicates the conditions under which the picture is taken then the result would be an image pretty much the same as what would be seen at the site the photo was taken. This could be described as "ortho stereo."
An example would be the Realist format that was so popular in the late 1940s to mid-1950s and is still being used by some today. When these images are viewed using high-quality viewers, or seen with a properly set-up projector, the impression is, indeed, very close to being at the site of photography. Of course, it is seldom possible to duplicate the exact conditions under which the photo is taken, just as it is rarely possible to exactly match the original colors, but ortho stereo tries to duplicate the natural stereo impression as close as possible just as color photography tries to give a natural impression of color, even if it isn't an exact match.
The baseline used in such cases will be about 50mm to 80mm. This is what is generally referred to as a "normal" baseline, used in most stereo photography. There are, however, situations where it might be desirable to use a longer or shorter baseline. The factors to consider include the viewing method to be used and the goal in taking the picture.