At present we have four tags related to noise in images as follows: (numbers of questions in brackets)
As I see it:
noise is the general tag and suitable for questions related to what noise is, or for questions such as this where noise is not the main focus of the question, but is clearly a part of it.
noise-reduction is for questions such as this one, where the question is about minimising the amount of noise in an image in the first place, and
noise-removal is to do with post-processing photos to remove noise that is in an image.
I see little need for
iso-noise, as at the moment it seems to mostly be used to tag questions that are related to noise (but necessarily due solely to ISO, such as this question) or already contain both the
noise tags, such as this question.
What does everyone else think? Should I start re-tagging to tidy these tags up as per the above?