Saturday, September 1, 2007

Digital noise reduction

If you regularly shoot pictures in low-light you either have to use a flash, which distorts color badly in my experience, or shoot at a high ISO level. For a digital camera, high ISO really just means keeping the shutter open for a shorter period of time. This results in a noisy image because the CCD is a noisy image capture device (particularly when warm) and when you capture less light the camera has to turn the gain up more on the final image. The gain turns up the image, and also the noise. All cameras have algorithms to reduce noise, but since the camera has limited processing power, there is only so much improvement these algorithms can make. Post processing software on your PC can do a better job. One free/mostly functional demo program is Neat Image. It takes a bit of work to use it, but for important pictures it can really reduce the apparent noise without making your images look that much more blurry.

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