Stereo
Stereophotography, or stereo in short, is a technique in which a camera, specially designed or modified for this, takes two pictures at the time of the same scene. The two pictures are taken from a slightly different point of view, like the left eye and the right eye in human vision. When the two pictures are viewed with a stereo viewer, the left picture is shown to the left eye and the right picture to the right eye, and that gives a tridimensional effect.
There were two periods when stereophotography was very much in fashion. The first one was at the beginning of the XXth century, when stereo cameras were very widely available, and the second one was in the 1950s, with a more limited vogue effect.
The main formats for stereophotography were 6x13cm and 45x107mm for a pair of pictures on the cameras of the beginning of the XXth century that used glass plates. In the 1950s the cameras tended to adopt some variation around the 24x23mm size per picture on regular 35mm film. The Verascope F40 is usually considered the best 35mm stereo camera.
Today some enthusiasts still take stereo pictures. They are either using old cameras or they build their own one by taking two bodies of the same type and modifying them to join them together. Then viewing is made either with a viewer or by projecting slides meant to be viewed with special googles.
