A method and apparatus for optimizing the voltage supply of an image sensor pixel array to minimize pixel noise and maximize dynamic range is disclosed. The voltage supply is adjusted in response to the exposure level of the pixel array when it captures an image. The voltage supply is increased in higher exposure levels to expand the dynamic range of the pixel array. In lower exposure levels, when the full dynamic range of the pixel array is not utilized, the voltage supply is decreased to lower pixel noise level and reduce its effect on image quality.