ISO and Noise
The problem with digital noise is still acute. Even expensive
professional cameras produce noise at high ISO settings.
Not to mention consumer level cameras that perform well only at
ISO 50–100.
Most digital cameras offer the option of automatic
ISO setting (auto). In this case a camera chooses settings on its own basing on
the shooting conditions. As a result, one can easily get "noisy" photos
because the camera can decide to shoot at a high ISO value.
The following photo was taken in automatic mode. Some photos
from the same session were taken at ISO 400, others at 261 or 236.
But the result is the same – all of them are very noisy.
We take one of such photos and try to improve it.
A fragment of the picture in real size is shown below.
The added complication is that the photo was then saved in jpeg. This compression is responsible for the jpeg artifacts.
Open the image in a photo editor and call the plug-in AKVIS
Noise Buster.
Adjust the settings. We applied the following values: Fade 75%, Luminance
Noise Level 15, Luminance Smooth Level 2, Color
Noise Level 28,
Color Smooth Level 5, Blur 0, Sharpen
Edges 0.
It's all very subjective you may set other values for the parameters.
Apply filtration with these parameters by pressing the button  .
Apply the filtering result to the image by pressing the button  .
the fragment before filtration
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the fragment after filtration
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ISO and Noise