FAST LENS Russian patent published in 2000 - IPC

FIELD: optics. SUBSTANCE: fast lens has four components. The first and second components - positive menisci whose convexity faces the object, the third component-negative meniscus whose concavity faces the image, the fourth component is made as a biconvex lens. There are relations binding up the lens focal distances and its components, component thicknesses, air gaps, radii of curvature and refractive indices of components. The fast lens has an aperture ratio of at least 1:1.7 and an angle field exceeding 20 deg. EFFECT: improved image in field. 3 dwg