near point

The feature in a stereo image which appears to be nearest to the viewer.

Nimslo

The brand name, taken from the surnames of inventors Jerry Nims and Allen Lo, for a camera system intended primarily to produce lenticular autostereo prints, incorporating four lenses to record the same number of images (each of 4-perforations width) on 35mm film. The name is often used to identify the size of mask or mount developed to hold 4-perforation-wide pairs of transparencies made with this camera and its derivatives.

one-in-thirty rule

A rule-of-thumb calculation for determining the stereo base when using a non-standard camera lens separation, eg in hyper- or macro- stereography. To achieve optimum stereo depth, the separation of the centres of the camera lenses should be around one-thirtieth of the distance from the lenses to the closest subject matter in a scene. This 'rule' only holds good under certain optical conditions (eg where 'standard' focal-length lenses are used), and usually needs to be varied when, for example, lenses of longer or shorter than normal focal length are used.

orthostereoscopic image (adv.)

An image which appears to be correctly spaced as in the original view. See also, tautomorphic image.

orthoscopic image

A stereoscopic image viewed with its planes of depth in proper sequence, as opposed to an inverse (or pseudo) stereoscopic image.

over-and-under (coll.)

A form of stereo recording (on cine film) or viewing (of prints) in which the left and right images are positioned one above the other rather than side-by-side, and viewed with the aid of prisms or mirrors which deflect the light path to each eye accordingly, as in the proprietary Elmo (cine), KMQ and ViewMagic (prints) systems.