What is stereo photography? Stereoscopic or 3D photography is when two or more images are taken at different perspective so that the combination tricks the mind into seeing depth. Stereo photography requires taking ‘paired’ images and then a means to view those images so that each eye sees complementary views and the brain interprets the images as one scene with a 3D perception. How the paired images are presented determines what is needed by the viewer to successfully see the 3D image. 1950’s movies used an anaglyph process that presented the two images on top of each other with one view in cyan and the other in magenta. Wearing glasses with corresponding cyan and magenta lenses limited each eye to seeing the correct view to create 3D perception. Anaglyphs are still used for publication, such as comic books, but the color representation is skewed by the process. That means most photographers and VR (virtual reality) enthusiasts prefer process that don’t require changing colors in the image.
Recent technology (recent being relative to the nearly 200 years of photographic developments) have provided vast improvements over anaglyphs for projected stereo imagery. Active Shutter TVs work by only presenting the image intended for the left eye while blocking the right eye’s view, then reversing the process, and repeating this so rapidly that the interruptions do not interfere with the perceived fusion of the two images into a single 3D image. Since no edits are made to the image and only one image is shown at a time, active shutter systems can display true photo quality, but require powered glasses that sync with the TV. Passive 3D TVs theater use glasses that dont require power and thus are lighter with less chance of technical difficulties. Each lens in the passive 3D glasses is polarized to let a different image through, one horizontal and one vertical. The two images are shown at the same time Interleaved. The glasses lenses only let in the image needed for that eye. Both systems work fine but require expensive specialized equipment.
This website uses side by side images that when viewed by a VR Headset give the illusion of depth. Though your VR headset might be using a state of the art device to show the images, the process of viewing two images in a viewer dates back almost to the advent of photography. Prior to the advent of the TV most homes had a stereo card viewer. During the Victorian period photographers traveled the world send back images of exotic locations that would be printed and distributed in stores. Modern VR Headsets are just the continued evolution of these early stereo photography process.