A stereo camera has two identical lenses arranged side by side, whose spacing roughly corresponds to the average human interocular distance. When triggered, the camera simultaneously exposes two separate half-images from slightly different viewpoints onto the film.
Viewing these two images with a special stereo viewer (stereoscope) or merging them digitally creates a spatial, three-dimensional depth effect for the human brain. This method of plastic image representation has fascinated photographers since the early days of photographic history.
