base, stereo

The distance between the left and right lenses when taking a stereo pair; i.e.
(1) the lens separation in a conventional stereo camera or a pair of mono cameras;
(2) the distance between the lens viewpoints when taking sequential exposures.

Bates stereoscope

See Holmes stereoscope.

beamsplitter

An optical element that reflects and passes specified percentages of the light rays striking it.

(coll.) A device consisting of prisms and/or mirrors which can be attached to a mono camera to produce two side-by-side images (usually within a single frame). More accurately described as an image-splitter, as it does not split an individual beam into components. Because the groups of light rays forming the left and right images cross over as they pass through the camera lens, the recorded images end up in the correct configuration for stereo viewing without the need for the usual transposition

binocular viewer

A two-lensed device for viewing planar pictures where the use of both eyes give more comfortable viewing and enhances the impression of depth.

A stereoscope.

Brewster-type stereoscope

Named after Sir David Brewster, who invented the lensed, or 'lenticular', stereoscope in 1849. Now may be used to describe any type of box-form lensed stereoscope usually for viewing prints.