Digital Noise in Your Photography
If you’re old enough to remember Slade or Quiet Riot, you know that noize rocks — as long as you’re looking for a bit of multicolored speckly texture in your images. Like grain back in the film era, you can use a bit of digital noise in your images for artistic effect. Rather than avoid noise, you might want to enhance it.
On the other hand, if you’re looking for a satiny smooth finish on your digital images, you might want to minimize noise. Fortunately, the techniques for adding or avoiding noise involve the same sets of concepts:
ISO setting: To increase the amount of noise in your photos, switch to a high ISO setting, such as ISO 1600 or ISO 3200. The higher the setting, the more noisy speckles you see in your images. To decrease the amount of noise, use a lower ISO setting, such as ISO 100 or ISO 200.
Exposure time: Longer exposures (from 1 second to 30 seconds or more) increase the amount of noise in an image when the sensor heats up and begins to register that heat as spurious image information. If you want to minimize noise, use a larger f/stop and shorten the exposure time.
Software: Applications such as Photoshop or Photoshop Elements include Add Noise filters that you can use to spice up your photos with a little random grain (multicolored or monochrome, as you prefer). On the other hand, tools such as Noise Ninja can remove excess noise to a certain extent when you don’t want it.