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US 10,705,312 B2Granted
Focus control apparatus, image capturing apparatus, and focus control method
AssigneeCanon Kabushiki Kaisha
InventorsMasaki Kamba, Ryo Kawasaki
Life of this patent
Estimating the term…
Abstract
A focus control apparatus includes a controller configured to provide a focus control that holds an object distance on which an image capturing optical system is focused that includes a magnification varying lens and a focus lens, and a calculator configured to calculate a defocus amount by using information on lens sensitivity that represents a relationship between a unit moving amount of the magnification varying lens and a moving amount of an image plane in the image capturing optical system, and information on error amounts of stop positions of the magnification varying lens and that of the focus lens. The controller moves the focus lens in a moving range limited based on the defocus amount.
Claims29
An image capturing apparatus comprising:
- an image sensor configured to output a signal corresponding to an object image formed by an image capturing optical system;
- and
- at least one processor which executes a program stored in a memory, wherein the at least one processor functions as;
- a controller configured to provide a focus control that holds an object distance on which an image capturing optical system is focused that includes a magnification varying lens and a focus lens, and
- a calculator configured to calculate a defocus amount by using information on lens sensitivity that represents a relationship between a unit moving amount of the magnification varying lens and a moving amount of an image plane in the image capturing optical system, and information on error amounts of stop positions of the magnification varying lens and that of the focus lens,
- wherein the controller moves the focus lens in a moving range limited based on the defocus amount.
3 more elements
A focus control apparatus comprising:
- a temperature detector configured to detect a temperature of an image optical system, and
- at least one processor which executes a program stored in a memory, wherein the at least one processor functions as;
- a controller configured to provide a focus control that holds an object distance on which the image capturing optical system is focused that includes a focus lens;
- wherein the controller moves the focus lens in a moving range limited based on a change amount of the temperature in the focus control when the change amount of the temperature from reference temperature is higher than a predetermined thermal change amount.
1 more element
An image capturing apparatus comprising:
- an image sensor configured to output a signal corresponding to an object image formed by an image capturing optical system;
- and
- a focus control apparatus that includes;
- a temperature detector configures to detect a temperature of the image capturing optical system;
- and
- at least one processor which executes a program stored in a memory, wherein the at least one processor functions as;
- a controller configured to provide a focus control that holds an object distance on which an image capturing optical system is focused that includes a focus lens,
- wherein the controller moves the focus lens in a moving range limited based on a change amount of the temperature in the focus control when the change amount of the temperature from reference temperature is higher than a predetermined thermal change amount.
5 more elements
A focus control method comprising the steps of:
- providing a focus control that holds an object distance on which an image capturing optical system is focused that includes a focus lens;
- and
- detecting a temperature of the image capturing optical system,
- wherein the focus control moves the focus lens in a moving range limited based on a change amount of the temperature in the focus control when the change amount of the temperature from reference temperature is higher than a predetermined thermal change amount.
1 more element
A focus control apparatus comprising at least one processor which executes a program stored in a memory, wherein the at least one processor functions as;
- a controller configured to control a focus lens so as to hold an object distance on which an image capturing optical system is focused, and controls the focus lens based on one of a plurality of focus position correction modes that correct a focus position in accordance with a change of a temperature, and
- wherein the focus position correction modes include a first focus position correction mode that moves the focus lens in a holding direction of the object distance without performing the focus control in accordance with a change amount of the temperature, a second focus position correction mode that moves the focus lens by the focus control in a moving range that contains a position of the focus lens moved by the first thermal focus correction, in accordance with the change amount of the temperature, and a third focus position correction mode that contains the first focus position correction mode and the second focus position correction mode in accordance with the change amount of the temperature, and
- wherein the controller controls the focus lens based on one of the first focus position correction mode, the second focus position correction mode, and the third focus position correction mode, selected by a user.
A focus control method comprising the steps of:
- providing a focus control that holds an object distance on which an image capturing optical system is focused that includes a magnification varying lens and a focus lens, and
- calculating a defocus amount by using information on lens sensitivity that represents a relationship between a unit moving amount of the magnification varying lens and a moving amount of an image plane in the image capturing optical system, and information on error amounts of stop positions of the magnification varying lens and that of the focus lens,
- wherein the focus control moves the focus lens in a moving range limited based on the defocus amount.
Dependencies are inferred from the claim text.