Provided are an image sensor and a method of sensing the same. The image sensor includes: a light receiving device; a signal conversion unit including a transfer transistor having a plurality of transfer gates and for converting photocharges generated by the light receiving device into a voltage to output the voltage; and a sensing control unit for generating at least two reset signals and/or at least two transfer signals applied to the transfer gates of the transfer transistor during a one-time photosensing cycle. The image sensor is obtained by changing the structure and driving method of a transfer transistor of a typical 4-transistor CMOS image sensor and employs a deep depletion operation and a multiple reset operation, thereby reducing an image lag and increasing the well capacity of the light receiving device.