Control apparatus which sets defocus amount used for focusing, image capturing apparatus, control method, and storage medium

An image capturing apparatus that acquires a first signal and a second signal corresponding to output signals from a first photoelectric converter and a second photoelectric converter, the image capturing apparatus comprising:

• an image sensor that includes the first photoelectric converter and the second photoelectric converter configured to receive light fluxes that have passed different pupil areas in an image capturing optical system;
• a memory device that stores a set of instructions;
• and
• at least one processor that executes the set of instructions to function as:
• a calculator configured to calculate a first defocus amount based on the first signal and the second signal in a first frequency band after each filter process by a plurality of filter processes having different bands for the first signal and the second signal, and to calculate a second defocus amount and a first reliability based on the first signal and the second signal in a second frequency band higher than the first frequency band, wherein the calculator calculates the first reliability based on a standard deviation of a plurality of defocus amounts relating on a correlation variation amount between the first signal and the second signal;
• and
• a controller configured to select a defocus amount used for focusing among th plurality of defocus amounts based on the first reliability,
• wherein the controller selects the second defocus amount as the defocus amount used for the focusing when the first reliability is equal to or higher than a first reference reliability.

A control method comprising:

• an acquiring step configured to acquire a first signal and a second signal corresponding to light fluxes that have passed different pupil areas in an image capturing optical system;
• a calculating step configured to calculate a first defocus amount based on the first signal and the second signal in a first frequency band after each filter process by a plurality of filter processes having different bands for the first signal and the second signal, and to calculate a second defocus amount and a first reliability based on the first signal and the second signal in a second frequency band higher than the first frequency band, wherein the calculating step calculates the first reliability based on a standard deviation of a plurality of defocus amounts relating on a correlation variation amount between the first signal and the second signal;
• and
• a selecting step configured to select a defocus amount used for focusing among the plurality of defocus amounts based on the first reliability,
• wherein the selecting step selects the second defocus amount as t defocus amount used for the focusing when the first reliability is equal to or higher than a first reference reliability.

A non-transitory storage medium storing a program that enables a computer to execute a control method that includes:

• an acquiring step configured to acquire a first signal and a second signal corresponding to light fluxes that have passed different pupil areas in an image capturing optical system;
• a calculating step configured to calculate a first defocus amount based on the first signal and the second signal in a first frequency band after each filter process by a plurality of filter processes having different bands for the first signal and the second signal, and to calculate a second defocus amount and a first reliability based on the first signal and the second signal in a second frequency band higher than the first frequency band, wherein the calculating step calculates the first reliability based on a standard deviation of a plurality of defocus amounts relating on a correlation variation amount between the first signal and the second signal;
• and
• a selecting step configured to select a defocus amount used for focusing among the plurality of defocus amounts based on the first reliability,
• wherein the selecting step selects the second defocus amount as the defocus amount used for the focusing when the first reliability is equal to or higher than a first reference reliability.