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Sample shot using Solux bulbs with a measured color temperature of approximately 4100K. Solux bulbs are full spectrum bulbs very similar to sunlight in their color rendering. The low color temperature light (more yellow) might contribute to slightly more noise than daylight-balanced shooting, making this example a good one for noise. Introduction I rarely use noise reduction as I do most shooting at an ISO of 800 or slower, which usually requires little attention to noise. However, while preparing the Nikon D2X vs D200 review, I investigated in-camera noise reduction and decided to compare it to noise reduction in Nikon Capture. This article isn’t really a review, but instead shows some of the results that can be expected from software noise reduction in Nikon Capture (version 4.4.1). It is important to realize that “” has no discernible effect with RAW (NEF) files, at least according to my tests. Instead, all it seems to accomplish is to default the setting in Nikon Capture to whatever was set in the camera. By comparison, “” has a pronounced effect when shooting raw—a “dark frame” is utilized by the camera at the time of exposure, doubling the exposure time, and the resulting image is largely free of bright speckles. The Nikon Capture “” window is shown below. 
Speed Using Nikon Capture’s noise reduction requires a fast computer. On a dual 2.5GHz Powermac G5 with 7GB RAM and MacOS 10.4.4, processing the raw image for this example took just 7 seconds without Noise Reduction off, but 50 seconds with Noise Reduction on, a 7-fold increase in time. Both CPUs were 100% utilized for that 50 seconds, so don’t plan on getting a lot of work done if you’re batch-processing 500 images with Noise Reduction enabled—plan on buying a PowerMac G5 Quad (4 cores). Example—high-contrast fine detail This resolution chart crops shown below demonstrate that Nikon Capture’s noise reduction has no negative effects on high-contrast detail, while helping to eliminate some discoloration.
Example—large crop If you have Adobe Photoshop or a similar program, you might want to paste the images below into a layered file so as to be able to click layers on/off to see the changes more conveniently—that would be for your own temporary and personal use of course. Alternately, view the large table for side-by-side comparisons. Sharpness = 5
Sharpness = 10 Increasing the sharpness parameter brings back some of the sharpness lost to the noise reduction. The same crops are shown below with Sharpness = 10 instead of 5.
Conclusions Nikon Capture’s noise reduction works well. At higher settings, overall color saturation seems to be decreased; this is most obvious in the large table with the images side-by-side. At Sharpness = 5, higher values of Intensity do blur image detail in lower contrast and darker areas, but leave it intact in brighter, high-contrast areas. Intensity values from 10 to 30 (depending on the image) are a good place to start, producing significant noise reduction with only minor loss of detail. At Sharpness = 10, higher values of Intensity are offset by the higher sharpness value. The net effect removes the color from the noisy areas, while retaining the grainy look. Higher level of Intensity may be used with higher Sharpness values. Overall color saturation declines, as if the whole image was desaturated. This might be mitigated by further post-processing in which color saturation is increased. Those needing frequent noise reduction might want to compare other solutions, such as NeatImage or Noise Ninja. I can offer no advice (yet) as to how those programs compare to Nikon Capture.
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