Image capturing apparatus, control method therefor, and storage medium

An image capturing apparatus, comprising:

• a plurality of pixels arranged in a matrix, each pixel including a photoelectric conversion portion;
• a column output line to which the plurality of pixels output analog signals on a column-by-column basis;
• an AD converter that converts the analog signals output from the plurality of pixels via the column output line into digital signals;
• a setting unit that sets one of a first driving mode and a second driving mode, the first driving mode causing the AD converter to convert the analog signals into the digital signals with a resolution of n bits, the second driving mode causing the AD converter to convert the analog signals into the digital signals with a resolution of m bits, n being an integer larger than or equal to two, m being a positive integer smaller than n;
• and
• a controller that performs control to make an operation period shorter when the setting unit has set the second driving mode than when the setting unit has set the first driving mode, the operation period being a period from a start of the outputting of the analog signals from the plurality of pixels to the column output line to a start of an operation of converting the analog signals into the digital signals in the AD converter.