A survey shows that DSC users have complaint on poor image quality of their cameras under dark conditions. By analyzing those “disappointing” photos we concluded that it is useful to increase ISO speed of a camera to get faster shutter speed and reduce the chance of camera shake or blurring of moving subjects, and also to achieve longer flash light range. But higher ISO speed sometimes induces unacceptable amount of luminance/chrominance noise. We have improved our image sensor and imageprocessing algorithm for reducing noise, and developed a compact DSC which can deliver acceptable photos even at its maximum ISO speed of 1600.