Series consists of 17 cameras designed to take identical images of the same subject from two lenses, approximately 2.5 inches apart or the same distance between human eyes. Cameras are able to make stereo pairs or single images. Cameras in this series range between ca.1850 and ca.1996.
The stereoscope was invented by Charles Wheatstone in 1838 to demonstrate binocular vision and its role in depth perception. Wheatstone used a pair of drawings to show how each eye could see a slight difference in each image, until the single images are superimposed onto each other through a stereoscope, revealing a three-dimensional effect. With the later establishment of photography, creation of Sir David Brewster's portable stereoscope in 1894 and the introduction of the wet-plate collodion process in 1851, did the stereoscopic industry rise to popularity.
Prior to the development of stereo-cameras, a single camera was used to produce either two daguerreotypes or calotypes in succession. The camera would be moved a few inches to one side between exposures in an attempt to produce pictures that looked identical or what was seen by the two eyes. However, this method was based off trial and error, as the quality of the three-dimensional effect might have been compromised by inadequate distance between exposures or alteration of camera angle, subject, and lighting conditions.
The two basic camera types designed to produce stereoscopic pairs are the single-lensed and double-lensed cameras. The double-lensed or binocular cameras allowed photographers to make simultaneous exposures for more accurate stereo photographs. The increasing demand for stereo imagery called for more portable cameras. Field cameras that folded to a compact size enabled photographers to leave the studio and produce stereos outdoors or previously inaccessible places. Later camera designs would have a standard format of 23x 24 mm with a focal length of 35mm and faster shutter speeds.