Features for reducing noise

In a perfect world there would never be an occasion when there was a need for photographers to use either a high ISO value or a long exposure and so all the images produced would be beautifully noise free. But alas this is not the case and all too regularly you will find yourself shooting in environments with very little light. Does this mean that we have to put up with noise-filled images for the sake of shooting convenience? The answer is no.

Most mid- to high-range digital cameras now contain specialized noise reduction or suppression features that help to minimize the appearance of random pixels in images produced with either high ISO or long exposure settings. These tools attempt to isolate and remove the errant pixels from the image, creating much cleaner and sharper images in the process.

For example, some cameras in the Nikon range, have a choice of two noise reduction systems that function in slightly different ways:

• NR (Noise Reduction) - This is the standard noise reduction setting that functions on all of the camera's different resolution settings as well as in conjunction with other features such as Best Shot Selector and Exposure Bracketing. Taking at least twice as long as a standard image to process and record, the camera's in-built software attempts to identify and eliminate noisy pixels in the image.

• Clear Image Mode - This setting minimizes noise and increases color gradation by capturing a sequence of three images of the one scene. The first two pictures are exposed with the shutter open, the third with the shutter closed. Using some sophisticated processing the three images are then compared and a single 'noise reduced' image is recorded. As several images are recorded it is recommended that a tripod be used when employing this feature.

The noise reduction features are activated via the camera's menu system. When noise reduction is in effect and the shutter speed is less than 1/30th of a second a small NR appears in the viewfinder. So when you are selecting a high resolution or long exposure time consider using your camera's noise reduction techniques to increase the quality of the resulting images. See Figure 16.7.

Photographers want the best quality images all the time so why not set up your camera so that the noise reduction features are left permanently on? In theory this sounds fine but in practice the extra processing and recording time taken to reduce the level of noise in an image would greatly increase the time period between successive shots. In most normal shooting circumstances, where noise isn't a problem, the extra time lag between shots would hamper the photographer's ability to shoot successive images quickly.

There is also a school of thought that says that any image enhancement activities (including noise reduction) are best undertaken back at the desktop with photo editing software such as Photoshop or Photoshop Elements. Photographers are then able to carefully customize the noise reduction process to suit each image which, in turn, should produce better results than the automatic and speedy approach used by the in-camera feature.

Digital Cameras For Beginners

Digital Cameras For Beginners

Although we usually tend to think of the digital camera as the best thing since sliced bread, there are both pros and cons with its use. Nothing is available on the market that does not have both a good and a bad side, but the key is to weigh the good against the bad in order to come up with the best of both worlds.

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