I noticed that when I underexpose a subject at relatively high ISO (e.g., 1000) and I adjust the exposure in Lightroom, a slight artifact will sometimes appear. I was wondering if this is normal or if my camera sensor has a problem.

Is this simply the result of trying to brighten up something that is already quite dark and was also underexposed at a relatively high ISO? Is there a name for this artifact?

This is a crop of the original underexposed RAW file. No artifacts are shown.

This is a crop of the original underexposed RAW file (no artifacts)

When I correct the exposure by adding +0.70 I see a little bit of the effect. However, for the sake of clearly showing the artifact here I'm including an overexposed version created by increasing the exposure in Lightroom by 3.0 stops. The artifact band full of red dots in the leg region becomes apparent.

Intentionally overexposed by adding +3.0 stops. The artifact is quite clear in the legs.

Thank you in advance.


1 Answer 1


It is called Chrominance noise. Yes, it is to be expected when underexposing shadows and then trying to push the exposure in post-processing.


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