Three-Dimensional Stereoscopic Photography
Stereoscopic photography allows to create the illusion of depth in an image from two two-dimensional images that have been obtained with a small horizontal displacement, similar to the way in which we capture reality. Our eyes are separated from each other, about 65 mm, so each eye sees an image.
An easy way to get 3d photographs is by making two images, horizontally separated the distance between our eyes. If we do not have a special camera with two lenses or two equal cameras together with synchronized shooting, we can use our usual camera by moving it sideways for the second photo. The first system allows to take photographs from 1 ‘ 5 meters, while the second is for landscapes, from 3 meters.
Our system, more rudimentary, can be used for static elements or distant landscapes, in which the changes between the two photographs are practically imperceptible.
The vertical changes are indifferent as for creation of sensation of volume (unless this difference is too big, in whose case they would create double vision or disorientation). Only the horizontal changes produced by the different place of the eyes, result in depth sensation.
For the brain to encode the image that corresponds to each eye by its different parallax, occur then the depth effect, we must use a viewer anaglyph, or special glasses polarized.