Image sensor and image capturing apparatus

An image capturing apparatus comprising:

• an image sensor, comprising:
• a pixel region in which a plurality of pixel units are arranged, each pixel unit having a micro-lens and a plurality of photoelectric conversion portions;
• a driving circuit that drives the pixel region to output signals from the pixel units in the pixel region;
• a memory that stores signals output from a part of the photoelectric conversion portions among the plurality of photoelectric conversion portions in each of the pixel units and signals output from all of the photoelectric conversion portions in each of the pixel units;
• an output circuit that outputs signals based on the signals output from the part of the photoelectric conversion portions among the plurality of photoelectric conversion portions in each of the pixel units and signals based on signals output from all of the photoelectric conversion portions in each of the pixel units outside of the image sensor;
• and
• a plurality of A/D converters that convert the signals output from the pixel units to the digital signals,
• wherein the pixel region is formed on a first semiconductor substrate, the memory is formed on a second semiconductor substrate that is different from the first semiconductor substrate, and the first and second semiconductor substrates are stacked on each other,
• the plurality of A/D converters are formed on the second semiconductor substrate,
• the memory is arranged after the A/D converters, and
• the memory is configured to store signals output from a plurality of rows of pixel units,
• a controller that determines a driving amount of an image capture lens using the output signals of the image sensor;
• and
• a driver that drives the image capture lens according to the driving amount.