Patent ID: 9742969
Date: 2017-08-22
CPC Classifications: H04N

Claim:
1. An attachment optical system to be detachably mounted between an image pickup optical system and an image pickup apparatus, comprising: a receiver configured to receive first information for correcting lateral chromatic aberrations that are caused by the image pickup optical system; a computing unit configured to derive, based on the first information and optical characteristics of the attachment optical system, second information for correcting lateral chromatic aberrations; and a transmitter configured to transmit the second information to the image pickup apparatus, wherein the first information and the second information comprise information for obtaining lateral chromatic aberration amounts under conditions regarding a zoom position, focus position, and f-number of the image pickup optical system, based on a ratio of an image height to be corrected on an image plane to a maximum image height, wherein the first information and the second information each indicate shift amounts of blue and red relative to green in a radial direction of a circle centered about an optical axis position, and wherein the shift amount of blue B where K represents a predetermined constant that is set in advance to the computing unit, r represents the ratio of the image height to be corrected on the image plane to the maximum image height, A 1B (r) represents the shift amount of blue relative to green in the first information, A 1R (r) represents the shift amount of red relative to green in the first information, and C 1B (r) and C 1R (r) respectively represent functions that have r as a variable.