Best Workflow for Noise Reduction with DNG Files in Helicon Focus?

[Octopus]

Hi everyone,
I shoot macro with an OM-1 + 90mm macro, using flash, diffuser, and usually handheld. My stacks are processed from DNG files, typically 15–30 images merged in Helicon Focus.

I have a question about the best noise-reduction workflow:

Is it better to apply noise reduction to all source files before creating the stack in Helicon Focus?
or
Is it preferable to run noise reduction only on the final output file after the stacking is done?

I’m especially interested in your experience regarding detail retention and avoiding artifacts in fine structures like insect hairs and droplets.

Thanks in advance!

[clausgiloi]

Forgive me for chiming in without having a definite answer, but I think that if noise is bad from low light it will almost certainly be better to denoise the source images.

For starters, you could denoise the raw files before they are linearized and make use of "raw denoise" type algorithms in LR or Topaz that are unavailable after de-mosaicing.

A reduction of noise in the input files can't help but aid the stacking methods in separating noise from detail.

That said, doing so would totally blow up my work flow, as I stack thousands of images at a time and the idea of denoising them all is not appealing. I set an ISO limit below the threshhold where I would consider it necessary.