Noise in digital images

Randomly-spaced speckles, called noise, can appear in digital images. Noise is similar to grain that appears in photos taken with traditional cameras using high ISO films.

Noise increases in photos taken with a digital camera using a high ISO number, usually over ISO 100. The higher the number, the more noise.

When noise is present, image detail and clarity are reduced, sometimes significantly. Noise is most noticeable in even areas of color such as shadows and in a sky.

Noise

Sections of sky photographed at different ISO numbers

Noise is especially visible when viewing a photo at 100% on a computer monitor. But when the image is reduced in size, noise may be barely visible. In fact, it may not be noticeable at all in small sized prints. The exception is when a very high ISO setting is used.

The good news is that there are steps to minimize, if not prevent, noise. There are also special software programs that do an effective job at noise reduction.

Preventing noise

If you keep your digital camera set to ISO 100 or below, you’ll rarely have problems with noise. The most notable exception is when there are dark, murky areas in a scene.

If you take a lot of low light photos, consider getting a digital single lens reflex camera. DSLRs have large sensors and produce very little noise compared to the vast majority of compacts, which have small sensors and limited light sensitivity. However, some newer compact digital cameras have better high ISO performance such as the Canon s90.

Shooting in low light

Using a flash can help prevent image noise if you stay within the recommended flash range for a camera. If you prefer not to use the flash, increase room lighting. Let outside light into the room through doors and windows. Turn on more room lights but also select an appropriate white balance setting.

If possible, use a tripod or other support such as a table top, to keep the camera steady rather than raise the ISO.

In-camera noise reduction

Some digital cameras include a Noise Reduction setting. When the setting is enabled, noise reduction takes place whenever shots are taken at very slow shutter speeds. While noise reduction works, some digital cameras  do a better job of it than others. When a large amount of noise appears in an image, detail will be smeared.

It should be pointed out to DSLR users that in-camera noise reduction my interfere with some camera functions, such as significantly slowing burst mode.

Shooting at very high ISO numbers

Some consumer digital cameras have a high sensitivity mode, or the capability of shooting at ISO 800, 1600 and higher. The quality of images produced using high ISO can be significantly degraded unless you have a camera capable of handling it well.

Test your digital camera to see the highest ISO number and the amount of noise it produces that you can tolerate.

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6 Responses

  1. Gail Bjork says:

    Sushi, if you want a compact camera that does well in low light, where noise is often at it’s worst, take a look at some of these cameras that do well in low light.

  2. Sushi says:

    Thank you very much for the helpful information. I didnt knew anything about this subject until recently because im planning to buy a camera soon. :D thanx again

  3. Gail Bjork says:

    Mr. Vijay, if your lenses are F mount they should still be usable with a Nikon dslr, however some older lenses can cause mechanical damage to more recent cameras. This article should give you more insight about using older lenses. I highly suggest you contact a place like B&H photo for assistance and advice before buying.

  4. Mr. Vijay Kumar says:

    I would appreciate if someone could help me with technical information regarding Nikon cameras. I have a Nikon F 75 camera bought some years ago but now I am interested in Digital cameras. I am wondering is it possible if I were to buy Nikon Digital  camera with body only but use it with my former Nikon AK  NIKKOR  28-100mm 1: 3.5-5.6G  and Nikkon Zoom lens  AK  NIKKOR  70-300mm 1:4-5.6G.

  5. Dione says:

    Thanks for this; it’s been the most helpful article I found on this subject!

  6. Cynthia Cable says:

    Hi Gail,  I enjoy reading your help site.  Good information, good review of topics.  I’m recommending it to friends.  Cynthia