Does Nikon D800 Apply NR in RAW Data Even When HIGH ISO NR is Turned Off?

Does Nikon D800 apply noise reduction even when High ISO NR is turned off in camera shooting menu? That seems to be what the Nikon D800 User Manual says as shown in the screen capture below. Does this affect only JPEG/TIFF output or NEF raw image as well?

Screenshot of Nikon D800 User Manual

Screenshot of Nikon D800 User Manual (D800_EN, p277).

Most likely not. It may not even affect the jpeg output from the camera.

The following chart shows JPEG file size vs ISO for images (Imaging Resource samples) shot with different NR settings (NR0=Off, NR1=Low, NR2=Normal, NR3=High). I also included the data for JPEG files converted using Nikon Capture NX 2 from NEF raw images with default NR setting and with NR turned completely off in the Develop module.

Nikon D800 file size vs ISO

Nikon D800 file size vs ISO (based on Imaging Resource Nikon D800 samples)

With higher ISO, the image will contain more noise. The noise makes it difficult to compress the image data therefore file size increases. If noise reduction is applied to the image data, the file size will be reduced. The more noise reduction is applied, the smaller the file will be.

The chart above shows that without noise reduction, the JPEG (exported from Capture NX 2 at 100% quality) file size increases smoothly with increased ISO. However the exported files have a sharp size reduction at ISO 1600 as shown in the green line. Even though the High ISO NR setting is turned off, Nikon Capture NX 2 still gets a hint to apply noise reduction. It is not hidden though. Under Develop->Camera Settings -> Noise Reduction, Color Noise Reduction is by default set to 3%. At the same time, the out-of-camera JPEG file does not show such a file size trend.

It appears that the manual is not very accurate. Can this be a software bug?

Posted in: Digital SLR Cameras on March 18th, 2012. Trackback URI
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Comments

  • Dean Andersen

    Interesting analysis of the images. I have done something similar with my D7000 and these results do not surprise me. Nikon “does things” even with the raw data when it is captured. I have done some tests not with a real scene but with the lens cap on the lens as the amount of noise should be more easily discernible. It is a good assumption that the file size is related to the amount of noise in the file. What I found interesting in my tests was that even at a constant ISO setting varying the shutter speed showed that noise reduction was being performed at several different speeds with a marked difference in processing happening at 1/4″ and longer.

    I think that no one would really be happy with the amount of noise in the raw files is the raw sensor data was actually written into the file but Nikon has undertaken to provide reasonable noise reduction even if it is undocumented.

    The raw files from my D7000 also have the setting to apply noise reduction turned on in Capture NX 2.3.1 for ISO 2000 and higher. It is set to zero for ISO 100-1600 but at ISO 2000 is set to 2 and increases up to 20 as the ISO is increased to max, even though the settings for High ISO noise reduction are turned off in the camera.

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