Image sensor, operation method thereof, and imaging device

An operation method for an image sensor, wherein

• the image sensor comprises an image sensing array on a semiconductor substrate for image sensing, the image sensing array comprising a plurality of first light sensing units arranged in an array;
• a first light sensor on the substrate, the first light sensor comprising a plurality of second light-sensing units arranged in an array, the second light-sensing units being positioned external to the array of the first light-sensing units,
• the method comprises:
• with the first light sensor, sensing ambient light and converting the ambient light into a first electrical signal;
• determining an intensity of the ambient light based on the first electrical signal;
• and
• controlling an operation of the image sensor based on the determined intensity.