Focus adjustment device, focus adjustment method, and non-transitory storage medium for storing focus adjustment programs for performing focus adjustment in response to image signals of an image pickup device including focus detection pixels

A focus adjustment method for performing focus adjustment by image signals of an image pickup device including focus detection pixels, the method comprising:

• controlling an image pickup operation of the image pickup device based on an exposure value for providing live view display to a display section based on the image signals of the image pickup device to acquire the image signals;
• performing focus detection based on image signals of the focus detection pixels, included in the image signals of the image pickup device, calculating a gain correction value to correct the image signals of the focus detection pixels based on a result of the focus detection, and performing focus detection by correcting image signals of focus detection pixels acquired in a next image pickup operation, with the gain correction value;
• providing instruction to start the focus adjustment;
• correcting the exposure value based on the gain correction value when the focus adjustment is performed based on the image signals of the focus detection pixels in accordance with the instruction to start the focus adjustment, and causing the image pickup device to perform an AF image pickup operation using the corrected exposure value as an exposure value for the AF image pickup operation;
• and
• performing focus detection based on the image signals of the focus detection pixels by the AF image pickup operation.

A non-transitory storage medium for storing computer-readable focus adjustment programs which are executed by a computer which performs focus adjustment by image signals of an image pickup device including focus detection pixels, when the focus adjust programs are executed by the computer, the focus adjust programs causing the computer to:

• control an image pickup operation of the image pickup device based on an exposure value for providing live view display to a display section based on the image signals of the image pickup device to acquire the image signals;
• perform focus detection based on image signals of the focus detection pixels, included in the image signals of the image pickup device, calculate a gain correction value to correct the image signals of the focus detection pixels based on a result of the focus detection, and perform focus detection by correcting image signals of focus detection pixels acquired in a next image pickup operation, with the gain correction value;
• provide instruction to start the focus adjustment;
• correct the exposure value based on the gain correction value when the focus adjustment is performed based on the image signals of the focus detection pixels in accordance with the instruction to start the focus adjustment, and cause the image pickup device to perform an AF image pickup operation using the corrected exposure value as an exposure value for the AF image pickup operation;
• and
• perform focus detection based on the image signals of the focus detection pixels by the AF image pickup operation.