In film, the term 3-D (or 3D) is used to describe any visual presentation system that attempts to maintain or recreate moving images of the third dimension, the illusion of depth as seen by the viewer.
The technique usually involves filming two images simultaneously, with two cameras positioned side by side, generally facing each other and filming at a 90 degree angle via mirrors, in perfect synchronization and with identical technical characteristics. When viewed in such a way that each eye sees its photographed counterpart, the viewerâ€™s visual cortex will interpret the pair of images as a single three-dimensional image. Modern computer technology also allows for the production of pseudo-3D films using CGI and without the need for dual cameras.
The stereoscopic era of motion pictures began in the late 1890s when British film pioneer William Friese-Greene filed a patent for a 3-D movie process. In his patent, two films were projected side by side on screen. The viewer looked through a stereoscope to converge the two images. Because of the obtrusive mechanics behind this method, theatrical use was not practical.
Frederick Eugene Ives patented his stereo camera rig in 1900. The camera had 2 lenses attached together, 1 3/4 inches apart.
Early in December 1922, William Van Doren Kelley cashed in on the growing interest in 3-D films started by Fairallâ€™s demonstration and shot footage with a camera system of his own design. Kelley then struck a deal with Samuel â€œRoxyâ€ Rothafel to premiere the first in his series of â€œPlasticonâ€ shorts entitled Movies of the Future at the Rivoli Theater in New York City.
Kelley, who was primarily a producer of color films, used his color system, Prizma, to print his anaglyph films. In early 1923, he shopped around a second Plasticon entitled Through the Trees – Washington D.C., shot by William T. Crespinel, which consisted of stereoscopic views of Washington, D.C., but found no buyers. Also in December 1922, Laurens Hammond (later inventor of the Hammond organ) and William F. Cassidy unveiled their Teleview system. Teleview was the earliest alternate-frame sequencing form of projection. Through the use of two interlocked projectors, alternating left/right frames were projected one after another in rapid succession. Synchronized viewers attached to the arm-rests of the seats in the theater open and closed at the same time, and took advantage of the viewerâ€™s persistence of vision, thereby creating a true stereoscopic image.
Most films to date are not 3-D; because of the difficulty of displaying in that format; it is more of a movie gimmick rather than a standard movie feature.