Patent Number: 6,297,912

Title: Zoom lens having low-pass phase filter, lens system having low-pass phase filter, and camera having the same zoom lens or lens system

Abstract: A lens system having a magnification changing function comprises a plurality of lens units, an aperture diaphragm, and a low-pass phase filter. At least one lens unit contributing to the magnification changing function is disposed on the image side of the aperture diaphragm. The low-pass phase filter is disposed appropriately away from the image plane. In one aspect, most of the magnification changing function is executed by the lens units disposed on the object side of the low-pass phase filter. In another aspect, the low-pass filter is constructed to be movable along the optical axis or inside or outside the optical path. In still another aspect, the low-pass filter has a variable characteristic. In further different aspect, the characteristic of the low-pass filter is determined so as to optimize the low-pass effect. Accordingly, a small-sized and inexpensive zoom lens or lens system that is capable of obtaining a substantially necessary low-pass effect regardless of the magnification condition, and a camera comprising the same zoom lens or lens system, can be provided.

Inventors: Goto; Hisashi (Tokyo, JP)

Assignee: Olympus Optical Co. Ltd.

International Classification: G02B 15/16 (20060101); G02B 015/14 (); G02B 005/20 ()

Expiration Date: 10/02/2018