Originally Posted by
arash_hazeghi
No, D3/D700/D3s do not apply in-camera NR at ISO 1600 because it is too low for them, there is hardly any noise in these cameras at ISO 1600 and a scene like this. The fine grain that you see in the BG is a result of down-sampling and sharpening which will highly exaggerate whatever residual noise that might be there , you should always apply noise reduction on the BG separately as the final step when you downsample the images.
In-camera NR is generally poor and it is only applied to JPEG files, it does not affect RAW capture, if you use ACR in-camera NR settings will be ignored. If you use manufacturer converter it will read an apply those settings to the RAW, but you can disable it. Any way, in-camera NR should be avoided as it often chews up the buffer too.
Hope this helps