USING
NOISE REDUCTION
The
higher the ISO sensitivity is set, the more likely the image
is to have random “noise” appear. This noise is
randomly-spaced pixels that do not reflect the accurate colors
of the surrounding pixels. The effect is not unlike “grain”
in a film image. With the D2x it is not possible to add noise
reduction until you reach 400 ISO, and even then only if YOU
think it needs it. The D2x does a great job with noise all
the way up to 800 ISO, and even beyond.
I
generally don't use extra noise reduction because it tends
to lower the sharpness of the overall image. Others use Noise
Reduction frequently. I've found that most people are used
to seeing a little bit of grain in an image and don’t
really notice digital noise unless it is very bad. The D2x
defaults to a “normal” amount of noise reduction
after you set your D2x to any ISO value 400 or above. We’ll
discuss this in more detail in a moment.
Let’s
look at a few pictures without and with noise reduction, and
you can decide what looks best.
In
Figure 7, 8, and 9 below, you'll see images without and with
noise reduction. Figure 7 is at 400 ISO, Figure 8 is at 800
ISO, and Figure 9 is at 3200 ISO (HI-2):



Here are the series of menu screen
used to set HIGH ISO Noise Reduction. (See also page 173 of
the D2x manual):

Select the Shooting menu, scroll
up or down to find High ISO NR, scroll right and select NORM,
HIGH, or OFF.
NORM is the factory default, and provides
whatever Nikon thinks is a normal amount of noise reduction
to images set to ISO values between 400 and HI-2. There is
also a HIGH setting, which provides even more noise reduction.
The images in Figures 7-9 are shown with HIGH noise reduction
enabled.
Finally, there is the OFF selection which
applies NO noise reduction at all in the range of 400-800
ISO.
Remember
that the D2x always applies some noise reduction in HI-1 and
HI-2 modes, even if you have noise reduction turned OFF. And,
even with noise reduction enabled there is NO noise reduction
applied to any images below 400 ISO.