Introduction

Stereoscopic 3D photography has been around since about 1840. Originally, it referred to the optical illusion of depth in still photographs. Early stereoscopes, like the one pictured above from 1859, displayed two nearly identical photographs, one seen only by the left eye and one seen only by the right eye. The observer would look through the two lenses and their brain would combine the two photos into a single image that appeared to have three-dimensional depth.