The DNR (Digital Noise Reduction) feature helps reduce what is known as image noise, i.e. the drop-in that can happen during a recording. This noise is caused by the amplification of the ISO sensitivity adjustment signal (sensitivity of film to light), provided by the sensor before and after digitization. It is higher at night. It gives a clearer or darker, more granular character to the image, a bit like dust. But most importantly, this drop-in takes the place of pixels on the recorded image and the image loses a lot of detail. The digital multidimensional noise reduction is possible through the integration of algorithms of the image processor built-into the cameras. This reduces the ISO adjustment noise to a minimum, also providing clarity with a lot more details, particularly at night. This also reduces the size of the recorded image.