IMAGE SENSOR AND IMAGING DEVICE INCLUDING THE SAME

An imaging device includes a pixel array with a plurality of pixels each configured to generate a reset signal and an image signal, a sampling circuit including a plurality of samplers connected to column lines, where each sampler generates a first comparison signal by comparing the reset signal with a ramp signal and generates a second comparison signal by comparing the image signal with the ramp signal. An ADC converts each of the first and second comparison signals into a digital signal. Each sampler performs an auto-zero operation for initializing itself before performing the comparing with respect to the reset signal in a first mode, and performs a respective auto-zero operation before performing the comparing for each of the reset signal and the image signal in a second mode.