FAST LENS Russian patent published in 1998 - IPC

FIELD: moving picture equipment. SUBSTANCE: fast lens has two components separated by aperture diaphragm. First component includes positive and two negative menisci, facing the picture with their concavity, and biconvex lens. Second component consists of biconvex lens, biconcave lens, double-lens positive meniscus, facing the picture with its convexity, and biconvex lens. Installed in front of first component are: first element which is negative meniscus facing the picture with its concavity. Absolute value of focal power is not more than 0.15 and not less than 0.05 the focal power of entire lens; second element which is biconvex lens. Its focal power makes up not more than 0.1 and not less than 0.01 the focal power of entire lens. Second component is provided with biconvex lens which is the last one in fast lens. Eleven-component lens has the following technical data: relative aperture of 1: 1.2, field of vision of 75 deg. 30', relation of S' to F' equal to 1.94, where S' is rear apical section of lens and F' is lens focal distance. EFFECT: enlargement of rear focal section at higher quality of picture. 1 tbl, 3 dwg