noise threshold and tone mapping

[zaar]

Hello!

I wonder if the noise threshold is affected by the tone mapping? As I understand the noise measurement is based on the local contrast between pixels, right? And tone mapping and LUTs can affect the contrast, so does that in effect change when the render limit kick in? Will I get a longer and cleaner render if I increase the contrast with LUTs? Because I have a feeling that I'm getting shorter but noiseier renders when revising an old project, but rendering with my LUT off, because that gets applied in post. But it's just a feeling, I don't have any numbers and that was months ago on a different Corona version also.

[Aram Avetisyan]

Hi,

Noise level is calculated for the render before it is tone mapped. Generally tone mapping should have nothing to do with noise (and noise level) but if you get less noisy render with tone mapping/post-processing (e.g. sharpening, blurring) that does not affect the calculated noise level.

[zaar]

ok, that's good to know, thanks! Makes sense to do it that way. And my feeling was probably just a feeling then.

[maru]

The only tone mapping operator which affects the way the image is rendered is exposure. And if I remember correctly, it is only the 1st exposure operator on the list. So a scene with exposure at -5 will render differently in terms of noise and sampling than the same scene re-rendered with exposure +5.

Also, as far as I know, noise level is not calculated based on contrast between pixels, it's more than that.

[leo_surrealismo]

Hi Maru, let's say I have an animated 360° camera. Each frame moves between spaces and has different exposure values.
Is the noise calculation based on each frame individually, or is it determined by the exposure of the first frame?

[maru]

Each frame individually.