Abstract

Ordinary security door peepers are inexpensive wide-angle viewing devices. They can be used in a variety of ways, some examples being the following: (1) Illumination can be analyzed by placing a peeper in the object plane of an imaging system. (2) Pupil aberrations are demonstrated with a door peeper placed on a light table that is viewed from various angles. (3) Zonal aberration effects in poorly corrected lenses are observed with a peeper at the image of a point source. (4) Conoscopic observation of thin crystals, e.g., a mica sheet, is performed by viewing the crystal between crossed Polaroids with diffuse rear illumination. (5) Wideangle illumination is obtained by inserting light from the narrow-field end of a peeper. (6) A poorman’s wide-angle photographic lens consists of a peeper preceding an ordinary camera.

© 1987 Optical Society of America