Noise
A term used in the field of audio engineering to describe interference that can lead to impure sounds and distortion. Noise may occur, for example, as a result of faulty microphones or recording equipment. In digital imaging, noise is a term used to describe the visible effect of interference on the CCD sensor. It appears as unwanted colour spots in an image - especially those taken at night with a slow shutter speed. (Colour noise)
Noise reduction
In noise reduction mode, the camera takes two shots: the normal shot and one with the same exposure time but with the shutter closed. It is then able to determine the areas of an individual image that are susceptible to noise and compensate for this.
