Should I use a single denoising method with aggressive settings, or combine different methods?

Question

I shot some pictures at night, at ISO 3200, and they are of course extremely noisy. But I want to keep them, and make them as decently looking as I can.

I use Darktable as a workflow software, and it offers four different plugins for denoise. I don't know how any of them works, but even if I knew the underlying principle, I'm not so good at photographic theory to know which one would be best for my pictures. Usually I just pick one at random and leave it at the default presets. But with these extremely noisy pictures, I need stronger denoise.

So I was wondering, should I choose one method of denoise and turn the slider up until I can't stand the blur? Or is it better to use several denoising techniques at once, in the hope that they have different disadvantages which don't stack?

I post the different denoise modules here, maybe some of you can recognize their working principle based on their names and parameters they have.

I think that "equalizer" is uncommon, it is a tool for enhancing local contrast for different sizes of structures. It has a "denoise" preset, too. The others are pure denoise tools. The documentation says "raw denoise" comes from dcraw.

Answer 1

As you mention there are several denoise plugins in Darktable, they differs in the algorithm how they will fight noise, speed, artifacts produced, resource usage etc.

denoise (non-local means) - works on luma (lightness noise) and chroma (color noise)

denoise (bilateral filter) - works on each channel (R,G,B noise)

equalizer (exotic wavelets) - i suppose this works on both luma/chroma

rawdenoise - does only work on chroma noise and is faster then the others

I have no deep insight into those algorithms used but the most common used for fighting ISO noise is using raw denoise, i also tend to use normal blending with raw denoise to bring back details using the opacity slider.