Patent ID: 8717682
Filing Date: 2014-05-06
Classification: G02B,G03B,H04N

Abstract:
1. A single focal length lens system, in order from an object side to an image side, comprising: at least a front lens unit which has positive optical power or negative optical power, and which does not move along an optical axis but is fixed in focusing from an infinity in-focus condition to a close-object in-focus condition; a focusing lens unit which has positive optical power, and which moves along the optical axis in focusing; and a rear lens unit which has negative optical power, and which does not move along the optical axis but is fixed in focusing, wherein: the focusing lens unit includes: a cemented lens element composed of a lens element having negative optical power and a lens element having positive optical power which are cemented with each other; and a single lens element which is located on the image side relative to the cemented lens element, and which has positive optical power and an aspheric surface, the rear lens unit is composed of one single lens element, an aperture diaphragm is located between the front lens unit and the focusing lens unit, the following condition (2) is satisfied: where f f the following condition (3) is satisfied: where f