FIVE-LENS WIDE-APERTURE OBJECTIVE Russian patent published in 1998 - IPC

FIELD: television cameras. SUBSTANCE: objective has first lens which is negative meniscus facing the space of objects with its convex radius. It has second, third and fourth single double- convex lenses. Second lens thickness along optical axis is at least 0.6 x f, and not more than 0.9 x f, where f is focal distance of objective. Distance between second and third lenses is not less than 0.9 x f and not more than 1.5 x f, where f is focal distance of objective. Fifth lens is double- concave one. Thickness of air gap between fourth and fifth lenses makes up 0.125+-0.05 mm. Aperture diaphragm is positioned between second and third lenses. EFFECT: more effective construction. 1 dwg, 1 tbl