Keep The Noise Down In Your Digital Images
It’s the grain of the digital age. Learn how to tame it.
The Dfine interface makes it easy to measure and reduce noise in a few clicks.
To counter noise and its effects, you need to start when you first take the picture. Many of the causes of noise can be controlled as you photograph. You can't change your sensor, nor can you change the way the sensor deals with long exposures, but you can control many of the other factors. Here are some ideas:
1. Avoid underexposure. With today's cameras, sensors are doing a great job of controlling noise and keeping it to a minimum. But as soon as exposure goes down, you can run into trouble with noise. Sometimes people say they don't worry about exposure because they shoot RAW. RAW files won't necessarily reduce noise. Exposure is important no matter what format you're using.
Just because you don't have blinking highlights on your LCD doesn't mean you have a good exposure. That simply can mean that you're well underexposed. What you can do is watch your exposure and look for blinking highlights—the warnings of overexposure. Use an exposure that just barely makes the blinking highlights go away.
Dfine Noise Reduction Dialog Box
2. Use low ISOs whenever you can. Be careful not to go overboard with this. I've had students turn in pictures that were blurry because they used too slow a shutter speed as a consequence of too low an ISO. It's better to have sharp pictures that have some noise than to have blurry pictures with no noise. Still, when you can, use lower ISO settings, especially if you can use a tripod or other support.
3. Turn on noise reduction for long exposures. When you turn on noise reduction for long exposures, you'll find that your exposures take more processing time before you see the results in your LCD. Typically, this time will be double your actual shutter-speed time; if you had a one-minute exposure, you might wait two minutes before you see an image. Sometimes photographers don't like this, so they turn off noise reduction. However, noise reduction for long exposures works and reduces the time spent later removing the noise.
4. Keep your camera cool. At times, we photograph in hot conditions. Look for opportunities to keep your camera from getting too hot; that means not leaving a black camera in the sun. If your camera is on a tripod or sitting out on the table, put a hat over it.
5. If you shoot JPEG, use the highest-quality setting. This minimizes any problems you might have with JPEG artifacts.