Image sensor and computing system having the same

A computing system comprising:

• an image sensor configured to generate a digital signal corresponding to an incident light;
• a storage device configured to store the digital signal;
• and
• a processor configured to control operations of the image sensor and the storage device,
• wherein the image sensor comprises:
• a pixel array configured to generate an analog signal by sensing the incident light;
• and
• an A/D conversion unit configured to generate the digital signal in a first operation mode by performing a sigma-delta A/D conversion and a cyclic A/D conversion with respect to the analog signal and to generate the digital signal in a second operation mode by performing a single-slope A/D conversion with respect to the analog signal.

A method of sensing an image, comprising:

• generating an analog signal by a pixel array in response to sensing an incident light;
• generating a digital signal in a first operation mode by performing a sigma-delta A/D conversion and a cyclic A/D conversion with respect to the analog signal by an analog-digital (A/D) conversion unit;
• and
• generating the digital signal in a second operation mode by performing a single-slope A/D conversion with respect to the analog signal by the analog-digital (A/D) conversion unit.