The Pentax K10D was tested using a Sigma 24-135 F2.8-4.5 lens. The images below show the performance of the Pentax K10D on a typical night scene at each ISO sensitivity. These are all 100% crops from full-resolution images taken at night using aperture priority, automatic white-balance and set ISO sensitivity.

Night shots are always the most difficult for any digital camera as noise is much more noticeable in dark areas and shadows. Since such scenes consist mostly of dark areas, they represent the worst cases of image noise. That being said, the Pentax K10D manages quite well. Noise levels increase steadily up to ISO 800 and make a jump at ISO 1600 which appears much noisier than ISO 800.