BARREL CONTRACTIBLE INNER FOCUS SUPER-TELEPHOTOGRAPHIC LENS SYSTEM HAVING SMALL-DIAMETER FOCUSING LENS GROUP

摘要

PROBLEM TO BE SOLVED: To provide an optical system being a barrel contractible inner focus super-telephotographic lens having a small-diameter focusing lens group whose entire length at the time of carrying is shortened while maintaining excellent optical characteristics.;SOLUTION: An objective is constituted of a metallic frame (front group GF) movable with respect to a mount and a metallic frame (rear group GR) fixed on the mount in order from an object side, and the front group GF is equipped with a 1st lens group G1 having positive refractive power, and the rear group GR is equipped with a 2nd lens group G2 having negative refractive power and a 3rd lens group G3 having positive refractive power. Then, focusing is performed by moving the 2nd lens group G2 along an optical axis, and the barrel of the lens system is contracted by shortening the distance between the surface of the 1st lens group G1 nearest to the image side and the surface of the 2nd lens group G2 nearest to the object side.;COPYRIGHT: (C)2003,JPO