Here the Pentax K20D was tested using the Pentax DA* 16-50 F2.8 lens. Images below show the performance of the Pentax K20D in a low-light situation 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. We can see that the K20D is not stellar in this area but manages to hold on to details reasonably well despite high noise levels at the higher ISO sensitivites. Up to ISO 400, image noise is very well controlled which results in highly usable images for large prints. At ISO 800, noise starts to appear but it is nothing to be alarmed with. Maximum print sizes have to be reduced starting at ISO 1600 due to loss of details. ISO 3200 is possibly usable for small prints, but ISO 6400 is not - at least not at these light levels. Note that all these images are taken with no image noise reduction applied. The Pentax K20D can apply noise reduction which does reduce noise but blurs the image in proportion to the noise reduction. This has no benefit on print sizes because the loss of noise is cancelled out by the loss of details.