OPTICAL SYSTEM FOR WIDE ANGLE CAMERA

摘要

PURPOSE: An optical system for a large caliber optical angle camera is provided to cancel a difference regarding the center of a lens and the brightness of the surrounding area by setting a surrounding light amount ratio to 70% or above. CONSTITUTION: A first lens(10) has a convex surface on the side of an object and also a concave surface towards the top side. A second lens(20) is a lens of negative magnifying power. A third lens(30) is lens of positive magnifying power. A diaphragm(70) selectively collects light from the third lens. A fourth lens(40) is an aspheric lens of positive magnifying power, which has a convex surface in each of the top side and the side of the object. A fifth lens(50) is a lens of positive magnifying power, which has a convex surface in each of the top side and the side of the object.