Although digital cameras have improved dramatically in their ability to handle high ISO and noise, there are still times when the level of noise in an image is bad enough to be a distraction.
And, if you're using an older camera, this problem is more pronounced, even at lower ISO settings.
Finally, with point and shoot type digicams, noise can be a factor even at ISO 400, in part because of the very small photosite size on these smaller sensors.
There are a number of options available for reducing noise in your images, including favorites such as Imagenomic's Noiseware, Noise Ninja, and Neat Image.
A slightly newer option from Topaz Labs is DeNoise, a plug-in for Photoshop and Lightroom. The latest release, 5.0 has added significant improvements in the output quality and the processing speed and warrants a fresh look.
The UI for DeNoise 5 is similar to other Topaz plug-ins, like Simplify and Adjust. On the left side of the window are all the available presets, which are quick adjustments that can be applied and used as is, or as a starting point for your adjustments.
The center panel takes up the bulk of the window and is your preview area. Tabs at the top of the window let you quickly swap between the original and the adjusted version. Along the right side are the preview navigator window and the actual adjustments.
The actual controls that are provided with Topaz DeNoise 5 are broken into three sections – Noise Reduction, Detail Recovery, and Debanding. To start with, you'll want to work on the noise reduction settings. DeNoise gives you control over both luminance noise and color noise with separate controls for shadow, highlight, and for the red and blue color channels – the two channels most affected by noise problems. Noise reduction can often lead to a problem with the black levels, taking away from the true blacks in your image and replacing them with a haze that looks unnatural. A new Correct Black Level control allows you to correct for this type of issue, restoring blacks to their correct levels.
Next, you'll use the Detail Adjustment options. Luminance noise reduction frequently softens contrast in the image, which can be recovered with the Recover Detail slider. A Reduce Blur control will enhance the contrast of edges in the image, and if your image starts to take on an unnatural smoothness, you can add a bit of grain with the Add Grain control.
Banding noise is very obvious when it's present in your image – parallel lines with strong color patterns. A new Debanding control gives you the ability to correct for this type of problem with both vertical and horizontal correction options.