Here the Pentax K-7 was tested using the Pentax DA* 55mm F1.4 lens. Images below show the performance of the Pentax K-7 in a low-light situation at each ISO sensitivity. These are 100% crops from maximum resolution images taken at night using aperture priority and set ISO sensitivity. Note a fluctuating street light and dropping light levels causes exposure and color to vary between shots.

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 K-7 performs very well 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 3200 due to loss of details. ISO 6400 is possibly usable for small prints. All these images are taken with no image noise reduction applied, so they can be improved in software. The Pentax K-7 itself can apply noise reduction too which reduces noise but blurs the image in proportion to the noise reduction. Usually this has no benefit on print sizes because the loss of noise is cancelled out by the loss of details.