An image sensor includes a pixel array including a plurality of pixels arranged in a matrix, the plurality of pixels configured to generate separate, respective pixel signals, a row driver configured to selectively read pixel signals generated by pixels of a plurality of rows of the pixel array, a binning circuitry configured to selectively sum or pass through the read pixel signals to generate binned pixel signals, a column array including a plurality of analog-to-digital converters (ADCs) configured to perform an analog-to-digital conversion on the binned pixel signals, and a mode selecting circuitry configured to control the row driver and the binning circuitry to change an operation mode of the image sensor based on a mode signal received at the image sensor to change an operation mode of the image sensor.