Focus adjusting apparatus, focus adjusting method, and image capturing apparatus

An image capturing apparatus, comprising at least one processor executing computer instructions stored in computer memory, or one circuitry, configured to function as:

• an image sensor that outputs an image signal through photoelectric conversion of light incident thereon;
• and
• the focus adjusting apparatus that includes:
• a tracking unit that detects an area corresponding to a subject to be tracked, and detects reliability of the area from the image signal corresponding to the area that has been output from the image sensor;
• a calculator that calculates a position of an imaging plane of the area;
• a prediction unit that predicts a position of an imaging plane at a time corresponding to a timing when the image signal is generated in the image sensor based on a history of positions of imaging planes of a focus adjustment area;
• a setting unit that sets a tolerance for positions of imaging planes based on the reliability;
• and
• a determination unit that determines the area corresponding to the subject as the focus adjustment area in a case where a difference between the position of the imaging plane calculated by the calculator and the position of the imaging plane predicted by the prediction unit is within the tolerance.

A focus adjusting method, comprising:

• detecting an area corresponding to a subject to be tracked, and detects reliability of the area from an image signal corresponding to the area that has been output from an image sensor;
• calculating a position of an imaging plane of the area;
• predicting a position of an imaging plane at a time corresponding to a timing when the image signal is generated in the image sensor based on a history of detected positions of imaging planes of a focus adjustment area;
• setting a tolerance for positions of imaging planes based on the detected reliability;
• and
• determining the area corresponding to the subject as the focus adjustment area in a case where a difference between the calculated position of the imaging plane and the predicted position of the imaging plane is within the tolerance.

A non-transitory computer-readable storage medium having stored therein a program, which, when executed by a processor, causes a computer or circuitry to function as each unit of the a focus adjusting apparatus that comprises:

• a tracking unit that detects an area corresponding to of a subject to be tracked, and detects reliability of the area from an image signal corresponding to the area that has been output from an image sensor;
• a calculator that calculates a position of an imaging plane of the area;
• a prediction unit that predicts a position of an imaging plane at a time corresponding to a timing when the image signal is generated in the image sensor based on a history of positions of imaging planes of a focus adjustment area;
• a setting unit that sets a tolerance for positions of imaging planes based on the reliability;
• and
• a determination unit that determines the area corresponding to the subject as the focus adjustment area in a case where a difference between the position of the imaging plane calculated by the calculator and the position of the imaging plane predicted by the prediction unit is within the tolerance.