Stereo Photography
by George Themelis & Jim Motley
Ohio Stereo Photographic Society
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A Crash Course in Stereo Photography by George Themelis & Jim Motley Ohio Stereo Photographic Society |
Stereo photography closely imitates viewing with both eyes. By alternating each eye we can easily convince ourselves that the two images seen by our eyes are not identical. Foreground objects appear to “jump” with respect to background objects.
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An example of a stereo pair (recorded with a single camera). Notice that the first bowling pin (center) appears to be slightly shifted with respect to the other two, between the two views. It is these small differences that generate the sense of depth when the images are viewed in stereo. Identical pictures hold no depth information! |
It is these differences (“binocular disparities”) that result in the sense of depth when the two images are “fused” by our brain in a process known as stereopsis. So, two healthy eyes and a function of the brain are needed to see in stereo.
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Two eyes are needed to see in stereo. The eyes are about 65 mm (2 1/2 inches) apart in our head and present two slightly different pictures to our brain. The pictures are then combined to form a single stereoscopic (with depth) image of our world. |
With this in mind it becomes clear that, for stereo photography, you must record not just one, but two images (a “stereo pair”) each from a different point of view, imitating the way the eyes see. When these two slightly different images are properly mounted and viewed in a stereo viewer, the result is usually “OH WOW!!!”
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If two pictures are recorded with lenses spaced 2.5 inches apart and are then presented to the eyes so that the left eye sees the left picture and the right eye sees the right picture, then the original scene is reproduced in its original dimensions, including depth. This is the basic principle of stereoscopic photography. |
Stereoscopic photography is as old as photography itself. The first ever photographs were made around 1838 and within less that 10 years, stereoview cards were being made and sold. Through the years, stereo has seen highs and lows in popularity among the public. From 1860 to 1920 stereoviews were essentially the home entertainment of the times. At one time, Keystone, based in Meadville, PA, was making 25,000 cards per day. Millions of stereo views and hundreds of thousands of stereoscopes were sold during this period of time. Stereoscopic views, seen through the stereoscope allowed people to travel to foreign lands in the comfort of their living room.
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View-Master is another popular stereo system, actually the most popular stereo entertainment systems of all times and the first that brought color into stereo. With color and depth, “it’s like being there!” It is estimated that over one billion reels and a hundred million viewers have been sold since the system was invented in 1938.
The “Golden Age” of do-it-yourself stereo was the period between about 1950 and early 1960's. Two main factors were Kodak's Kodachrome 35 mm film and the David White Co. of Milwaukee manufacturing their Realist stereo camera using this new film with its beautiful colors.
From 1947 until the mid 60s David White manufactured about 130,000 Realist cameras, which was about half of all the stereo cameras made during that period. Other brands included Revere, TDC Colorist, TDC Vivid, Kodak Stereo, and other lesser-known brands. These cameras are still used by many stereo enthusiasts today.
Long out of production “Classic” stereo cameras, most often Realists and Kodaks, are seen at Photo Shows and appear in auctions on the Internet. The market price is around $100-$200 but if you are lucky you can find them for less in flea markets or garage sales or even get one for free from friends or relatives who don't use them any more. Basic camera reconditioning might be required for cameras that have not been used for many years.
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| Stereo photography in the 50s was a complete system, which included things like stereo viewers, stereo projectors, books, and commercial stereo mounting. Stereo mounts, commercial mounting and even modern stereo cameras, viewers and projectors are still available today, but only through small number of manufacturers and resellers. Realist stereo system (left) and Kodak Stereo camera (right) are shown here. |
Isn't it amazing that some of these 40-50-year-old cameras are still used to make great stereo pictures? Most of these cameras use closely matched “Cooke triplet” three element lenses, which gave, and still give, good results. Here are a few things that you need to know about classic stereo cameras if you decide to use one of them:
The film format issue is usually not a problem. Currently manufactured stereo mounts, viewers and other supplies are available from a small number of companies. If you shoot slides, you can cut and mount your own film (just have the film returned uncut) using the standard stereo slide mounts, which are 1 5/8 by 4 inches (41x101 mm), or send them to Kodak who continues to offer a stereo slide mounting service. For commercial prints, there is at least one company that specializes in printing Realist format negatives, or you can work with your local developer to explain the format and size of prints you want.
Most 2-D photographers are aware of the rules for good photography, including good composition, exposure and focusing. Generally, the same rules apply in stereo photography with a few exceptions:
The lack of automation usually worries those who are “spoiled” by modern cameras. But if these stereo cameras were good enough for the layman in 1950, they are certainly good enough today. Light meters are useful but not necessary for getting good exposures. You can follow the exposure instructions printed inside the film box which are based on the “sunny 16 rule” (on a sunny day use f16 and 1/ASA where ASA is the film speed.)
For your first stereo picture use 100 ASA film and, on a sunny day, set the camera at f16 and 1/100s and focus at 15 feet. For sharp pictures from 7 ft to infinity you cannot go wrong with this combination! For indoor pictures a modern flash can be used with most stereo cameras. Many stereo cameras use unconventional flash shoes but adapters are usually available from stereo dealers (at least for the Realist and the Kodak).
For more details on using manual stereo cameras check the literature available from OSPS.
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| Pictures of family and travel have always been among the most popular subjects for stereo photography. (From Realist format slides, ca. 1950 - Note the lady at the left is standing in front of Notre Dame in France, holding a Stereo Realist camera!) |
Can non-stereo cameras take stereo pictures? Certainly! Stereo pairs can be taken by the simple method of shoot, shift, and shoot. Just shift the camera about 2 ½ inches by shifting your weight from your left foot to your right, between exposures. (This is sometimes called the “Cha-Cha” method for obvious reasons. The camera must be held level (as should any stereo camera) and the shift should be done horizontally with essentially no up or down movement. It is best not to have any movement in the scene between exposures. Even a slight movement of the leaves on a tree will stand out in stereo. Obviously, a slide bar leveled on a tripod would give better results than hand holding the camera.
If the nearest objects in the scene are around seven feet from the camera, a shift of about 2 ½ inches (like the spacing of most stereo camera lenses) is appropriate. For closer objects, a lesser shift and for more distance nearest objects, a greater shift is appropriate. Stereo pictures recorded with more than 2.5 inches shift are known as hyperstereos. This is a good way to photograph distant objects like a city from the top of a hill. When viewed in stereo a hyperstereo looks like a small-scale model of the object. Stereo pictures recorded with less than 2.5 inches are known as hypostereos. This is how a bee could view the world. A handy rule of thumb is the “1/30 rule” which states that the camera shift should be 1/30 of the distance to the nearest object (nearest object, not main subject).
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A regular SLR camera on a stereo slide bar (shown here is a slide bar by Bogen) is one of the most flexible and powerful stereo camera systems! |
Many systems are available, including:
Stereo photography is a two-step process. Recording the images is the first step. Viewing the resulting pair, i.e. making the left eye see the left image and the right eye see the right image, is the second and perhaps more challenging step. It usually requires that the images are mounted for viewing. As mentioned, for slides, the 1 5/8 by 4 inch stereo mount is commonly used and a variety of stereo viewers exist that handle this format. These range from small inexpensive cardboard or plastic units to more expensive viewers with internal illumination and achromatic lenses like the Realist “red button” viewer). Viewers are also available for 2x2x2 slides (a pair of slides kept in regular 35 mm mounts). Finally, those who work with prints can use wood or metal stereoscopes from the 1900s or modern versions. A versatile and inexpensive print viewer is the View-Magic viewer.
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The View Magic viewer requires that the two prints are placed one at the top of the other. This is a quick and easy way to view unmounted prints. |
Stereo slides can be shown to large audiences using polarized stereo projection. Stereo projectors are available with built-in polarizing filters. The audience must also wear polarizing glasses to see the projected images in stereo. This arrangement makes it possible for the left eye to see only the left image and the right eye to see only the right image. For 2x2x2 slides regular projectors with attached filters are used and make it possible to have stereo dissolve shows with 4 (sometimes 8!) projectors. The projecting screen must be a silver (lenticular or other type) to maintain polarization. Glass bead and plain white screens, which are often used for 2-D projection, will not work in stereo.
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Stereo projection is possible using a stereo projector from the 50s, like the popular TDC 116 seen in action here. Projection supplies (polarizing glasses, filters, silver screens etc.) are available new today. |
This overview has just scratched the surface of the diverse and fascinating subject of stereoscopic imaging. To learn more about stereo photography please visit our club or contact some of the sources listed in the directory below.
Jim Motley & George Themelis, OSPS