Nikon D90 High ISO Noise Reduction

The Nikon D90 delivers a noticeable advance in high-ISO image quality over the former D80. Its different noise-reduction settings also allow you quite a bit of flexibility in choosing how you want to make the trade-off between subject detail and noise levels. It's not clear that the "off" setting truly eliminates the noise processing altogether, but it is true that it leaves a lot of fine/subtle subject detail there for you to work with. The combination of shooting with NR turned off and using a good noise-filtering program after the fact can produce very clean images with lots of fine detail in them. (And of course, the D90's NEF RAW files have no noise-reduction processing applied to them at all, adhering to the true philosophy of RAW shooting.)

See for yourself how the noise reduction works under daylight-balanced lighting. Click on any of the crops below to see the corresponding full-sized image.

High ISO Noise Reduction Comparison Simulated Daylight
	Off	Low	Normal	High
I S O 8 0 0
	Off	Low	Normal	High
I S O 1 6 0 0
	Off	Low	Normal	High
I S O 3 2 0 0
	Off	Low	Normal	High
I S O 6 4 0 0

The above crops show the effects of the 4 levels of high ISO noise reduction, under our studio HMI lighting we use to simulate daylight. Note that some minimal NR is still performed at ISO 3200 and above when High ISO NR set to "Off". The difference between the "Off " and "Low " settings is quite subtle below ISO 3200. In fact, to our eyes, there's little to distinguish between Off and Low at ISO 800 and 1,600: In some ways, images shot with Off look softer than those shot with the Low setting. (We did check the EXIF headers with Nikon Viewer NX, and confirmed that the full resolution camera files on the server here were indeed shot with the settings as shown in the file names.

But how does the D90 compare to the more expensive D300? See the crops below.

High ISO Noise Reduction D90 vs D300 Comparison Simulated Daylight
ISO 800
	Off	Low	Normal	High
D90
D300
D90
D300
D90
D300
ISO 1600
D90
D300
D90
D300
D90
D300
ISO 3200
D90
D300
D90
D300
D90
D300
ISO 6400
D90
D300
D90
D300
D90
D300

The above crops compare the D90 (top row) versus the D300 (bottom row) of each set. We see very similar results, with the D300 having a slight but clearly discernible edge on detail at lower ISOs, and the D90 having slightly cleaner results than the D300 at ISO 3200 and 6400, but with a more processed look to them.