Interchangeable lens apparatus and image capturing apparatus capable of acquiring in-focus state at different image heights, and storage medium storing focusing program

Patent metadata

Field	Value
Publication number	US-10244157-B2
Application number	US-201514843209-A
Country	US
Kind code	B2
Filing date	Sep 2, 2015
Priority date	Sep 5, 2014
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

The interchangeable lens apparatus provided with an image capturing optical system and being detachably attachable to an image capturing apparatus, the image capturing apparatus being configured to detect a defocus amount of the image capturing optical system by using a signal acquired by photoelectric conversion of an optical image formed by the image capturing optical system. The interchangeable lens apparatus includes a focus lens included in the image capturing optical system, and a memory to store information on a focus sensitivity indicating a relation between a unit movement amount of the focus lens and a displacement amount of the optical image. The information on the focus sensitivity is information for enabling acquiring the focus sensitivity different depending on an image height.

First claim

What is claimed is:

1. An interchangeable lens apparatus provided with an image capturing optical system and being attachable to and detachable from an image capturing apparatus, the image capturing apparatus being configured to be able to detect a defocus amount of the image capturing optical system at plural different image heights using a signal acquired by photoelectric conversion of an optical image formed by the image capturing optical system, the interchangeable lens apparatus comprising:
a focus lens included in the image capturing optical system; and
a memory configured to store information on a focus sensitivity indicating a relation between a unit movement amount of the focus lens and a displacement amount of the optical image, the information on the focus sensitivity including a plurality of information for enabling acquiring the focus sensitivity different depending on an image height and different depending on pupil division directions in a detection of the defocus amount.

2. An interchangeable lens apparatus according to claim 1 , further comprising a processor configured to execute instructions stored in the memory to function as:
a sensitivity acquirer configured to receive, from the image capturing apparatus, information on the image height at which the defocus amount is detected and to acquire the focus sensitivity at the received image height by using the information on the focus sensitivity; and
a sensitivity sender configured to send the acquired focus sensitivity at the image height to the image capturing apparatus, the image capturing apparatus being configured to calculate a drive amount of the focus lens by using the focus sensitivity and the defocus amount.

3. An interchangeable lens apparatus according to claim 1 , further comprising a processor configured to execute instructions stored in the memory to function as:
a sensitivity acquirer configured to receive, from the image capturing apparatus, information on the image height at which the defocus amount is detected and to acquire the focus sensitivity at the received image height by using the information on the focus sensitivity; and
a drive amount calculator configured to calculate a drive amount of the focus lens by using the focus sensitivity at the received image height and the defocus amount received from the image capturing apparatus.

4. An interchangeable lens apparatus according to claim 3 , wherein, when h represents the image height, d(h) represents the defocus amount at the image height h, and S(h) represents the focus sensitivity at the image height h, the drive amount calculator calculates the drive amount X of the focus lens by using the following expression:
X=d ( h )/ S ( h ).

5. The interchangeable lens apparatus according to claim 1 , wherein the information on the focus sensitivity is a function enabling calculation of the focus sensitivity depending on the image height or a table containing the focus sensitivity corresponding to each image height.

6. The interchangeable lens apparatus according to claim 1 , wherein the information on the focus sensitivity is information for enabling acquiring the focus sensitivity different depending on the image height and on an azimuth direction.

7. The interchangeable lens apparatus according to claim 1 , further comprising a driving unit configured to drive the focus lens, wherein the driving unit drives the focus lens based on a movement amount of the focus lens received from the image capturing apparatus, the movement amount of the focus lens being obtained based on the information on the focus sensitivity which the interchangeable lens apparatus sends to the image capturing apparatus.

8. The interchangeable lens apparatus according to claim 1 , wherein the information on the focus sensitivity includes one or more coefficients used in a focus sensitivity function that enables calculating the focus sensitivity corresponding to the defocus detection image height.

9. The interchangeable lens apparatus according to claim 1 , wherein in each information of the plurality of information, a sagittal component and a meridional component are mixed at rates different depending on image heights.

10. The interchangeable lens apparatus according to claim 1 ,
further comprising a processor configured to execute instructions stored in the memory to function as a flag sender,
wherein the memory is configured to store flag information indicating whether the information on the focus sensitivity is stored in the memory, and
wherein the flag sender configured to send the flag information to the image capturing apparatus.

11. The interchangeable lens apparatus according to claim 10 ,
wherein the processor is further configured to execute instructions stored in the memory to function as a sensitivity sender configured to send the information on the focus sensitivity to the image capturing apparatus in response to receiving a request for the information on the focus sensitivity from the image capturing apparatus after the flag sender sends the flag information to the image capturing apparatus.

12. An image capturing apparatus attachable to and detachable from an interchangeable lens apparatus provided with an image capturing optical system including a focus lens, the image capturing apparatus comprising:
a defocus detector configured to detect a defocus amount of the image capturing optical system at plural different image heights using a signal acquired by photoelectric conversion of an optical image formed by the image capturing optical system;
a memory configured to store instructions; and
a processor configured to execute the instructions to function as:
a sensitivity acquirer configured to acquire a focus sensitivity indicating a relation between a unit movement amount of the focus lens and a displacement amount of the optical image based on information on the focus sensitivity and an image height at which the defocus amount is detected, the information on the focus sensitivity including a plurality of information for enabling acquiring the focus sensitivity different depending on an image height and different depending on pupil division directions in a detection of the defocus amount; and
a drive amount calculator configured to calculate a drive amount of the focus lens using the focus sensitivity corresponding to the image height and the defocus amount.

13. An image capturing apparatus according to claim 12 , wherein the sensitivity acquirer is configured to:
send, to the interchangeable lens apparatus, the information on the image height at which the defocus amount is detected; and
acquire, from the interchangeable lens apparatus, the focus sensitivity corresponding to the image height at which the defocus amount is detected.

14. The image capturing apparatus according to claim 12 , wherein, when h represents the image height, d(h) represents the defocus amount at the image height h, and S(h) represents the focus sensitivity at the image height h obtained by the sensitivity acquirer, the drive amount calculator calculates the drive amount X of the focus lens by using the following expression:
X=d ( h )/ S ( h ).

15. The image capturing apparatus according to claim 12 , wherein the information on the focus sensitivity includes one or more coefficients used in a focus sensitivity function that enables calculating the focus sensitivity corresponding to the defocus detection image height.

16. The image capturing apparatus according to claim 12 , wherein in each information of the plurality of information, a sagittal component, and a meridional component

Assignees

• Canon Kk

Inventors

• Sugita Shigenobu
• Kosaka Yuichi
• Nakamichi Takahito

Classifications

• H04N23/673

  based on contrast or high frequency components of image signals, e.g. hill climbing method · CPC title

• H04N23/663

  for controlling interchangeable camera parts based on electronic image sensor signals · CPC title

• H04N23/672 Primary

  based on the phase difference signals · CPC title

• G03B13/36

  Autofocus systems · CPC title

• G02B7/34

  using different areas in a pupil plane · CPC title