公开(公告)号：US20040109240A1

公开(公告)日：2004-06-10

申请号：US10724714

申请日：2003-12-02

Applicant: PENTAX Corporation

Inventor： Norio Sato ,  Toshiharu Suzuki

IPC: G02B015/14

CPC classification number: G02B7/102 ,  G02B5/205

Abstract: A lens barrel includes an optical system including a short focal length for a wide angle of view; and an ND filter in the shape of a disc which is provided on an optical axis of the optical system. An optical density of the ND filter decreases in a direction radially outwards from a center of the ND filter.

Abstract translation: 透镜镜筒包括用于广角视角的短焦距的光学系统; 以及设置在光学系统的光轴上的盘状的ND滤光器。 ND滤光器的光密度在ND滤光片的中心的径向向外的方向上减小。