This is a rather extreme example of digital camera noise reduction, but the camera used for this image is the fairly popular and affordable Nikon D40, so it is a valid example of a situation that many photographers find themselves in these days.
Before anyone writes me a comment, saying that I should not use ISO 3200, this is an example of what can be done, I took this picture specifically to illustrate what happens when you shoot at ISO 3200 with a Nikon D40 and what you can do in Lightroom to improve (or enhance) that image.
Personally I find noise (or grain in film terms) very attractive in some images and I want to know what I can do with my digital cameras. Not only at the 100 ISO perfect exposure end of the image but also at the extreme and most ragged end of digital noise.
Noise Reduction - Luminance 0 - Color 0
If you look in the picture, especially the road surface, you will see quite a lot of multi-colored “grain” which is the noise coming from the processor at ISO 3200.
Noise Reduction - Luminance 100 - Color 0
With the Luminance Noise Reduction at a value of 100 the “grain” has disappeared but the multi-colored noise is still very visible in the picture and kind of smudged looking.
Noise Reduction - Luminance 0 - Color 100
With the Color Noise Reduction set at 100 the color noise is gone but there is a fairly strong “grain”, I really don’t mind this result and in some instances could see using it on purpose.
Noise Reduction - Luminance 100 - Color 100
This is the maximum noise reduction setting for Color and Luminance and looks a bit too smudged to me.
Full Frame Image - Luminance 40 - Color 100
I find this setting fairly acceptable. it might not hold up to enlargement, but for me (and I assume a lot of other people) most of my images (not all of them for sure) are actually used at fairly small size.
I am of course not recommending that you can start shooting everything at ISO 3200, but whenever it is absolutely necessary, it is good to know that a usable image can be extracted from the results.