Tips to reduce noise?

kingofthedirt702

Hi, still figuring my way around Daz, this is my second render.

I've googled different ways of reducing noise but still haven't been able to get it where I want. I've let this render run for the entire 15K samples at 1080p. I also ran a render at 4K for around 7500 samples, and while I think it looks better, it also took twice as long (more than 2 hours) and is still pretty noisy. I think the background is okay, but the woman is very noisy, particularly her skin.

I know lighting is especially important in low light scenes but honestly I don't think she's that dimly lit, especially in comparison to her surroundings. The lighting on her is a 3 point setup, the exposure value is at 17 and the luminance for the main light is at around 70K. I've read that making the lighting brighter and using tonemapping to alter the exposure would help decrease the noise, but I've already tried it at the original exposure value of 13, 15, and now 17 and the results are quite similar. Is it that simple or would I have to make some other changes to the lighting? I'd prefer to keep the same mood/brightness.

I'd prefer to avoid denoisers and postwork for now if possible, maybe just advice for lighting and other render settings. I ran it through Intel's denoiser just to test it and it does result in a noticeable loss of detail on the skin. 

Taoz

Doesn't look like regular noise to me. Have you tried another skin texture?

kingofthedirt702

Taoz said:

Doesn't look like regular noise to me. Have you tried another skin texture?

 Just tried another paid skin as well as the base G8F. Looks a bit better (i think?) but still not great. The background clears up really quickly, even at 500 iterations there is still quite a bit of fireflies and noise but the overall clarity is good. The skin for some reason is just really grainy.

Taoz

That Nightclub environment has a lot of colored lights sources and things going on in the background, might cause some odd lighting effects I imagine.

Taoz

This is the G8F base skin in a very dark environment, after about only 300 iterations.  Light source for the character is a plane with Iray emission light. 

kingofthedirt702

Taoz said:

That Nightclub environment has a lot of colored lights sources and things going on in the background, might cause some odd lighting effects I imagine.

 Thanks, I'll try playing with some of the off-screen emissives. 

Hylas

Is the set a closed room? If so, that's almost certainly the problem.

Use IRAY section planes to make the out-of-frame walls invisible, thereby making it an open environment.

Then find an HDRI that more or less matches the mood of the room (maybe the dark blue one from this free set?) and apply it.

Does this make sense? Maybe I can find time to explain this further if needed.

Schaaka

kingofthedirt702 said:

Taoz said:

Doesn't look like regular noise to me. Have you tried another skin texture?

 Just tried another paid skin as well as the base G8F. Looks a bit better (i think?) but still not great. The background clears up really quickly, even at 500 iterations there is still quite a bit of fireflies and noise but the overall clarity is good. The skin for some reason is just really grainy.

One thing I've learned is that Daz has a really bad time rendering in low light situations.

I've tried pushing up the quality settings but it still leaves it grainy.

The denoiser while removes the grain makes the render look like a smudged painting.

Your best bet is to render all dark scenes in normal lighting and then go into your Tone Mapping in render settings and adjust them. Heres an example of a setting I use:

Explosure value = 15~, Shutter Speed = 256, F/Stop = 12, White Point = 1.0/0.8/0.3.

You can adjust those as needed to get the right lighted look but this is the main way Ive found to fight against the noise of darkness.

 

Richard Haseltine

Schaaka said:

kingofthedirt702 said:

Taoz said:

Doesn't look like regular noise to me. Have you tried another skin texture?

 Just tried another paid skin as well as the base G8F. Looks a bit better (i think?) but still not great. The background clears up really quickly, even at 500 iterations there is still quite a bit of fireflies and noise but the overall clarity is good. The skin for some reason is just really grainy.

One thing I've learned is that Daz has a really bad time rendering in low light situations.

I've tried pushing up the quality settings but it still leaves it grainy.

The denoiser while removes the grain makes the render look like a smudged painting.

Your best bet is to render all dark scenes in normal lighting and then go into your Tone Mapping in render settings and adjust them. Heres an example of a setting I use:

Explosure value = 15~, Shutter Speed = 256, F/Stop = 12, White Point = 1.0/0.8/0.3.

You can adjust those as needed to get the right lighted look but this is the main way Ive found to fight against the noise of darkness.

The issue is that Iray (rather than Daz [Studio}) is a path tracer - it tracks the bounces of the light from emitter to camera, using varying angles and averaging the results. In order for an area to stop being noisy it needs to receive enough hits to average out close to its "correct" value - with noirish or high-contrast lighting there will be a lot of areas that get relatively infrequent hits and so take a long time to attain their average value.

Convergence ration is a measure of how many pixels seem to have attained their final, average value - Render Quality determines how exacting the test for having achieved that final value is, so turning it up will make Iray slower to decalre the render done but won't affect how long it takes to reduce the noise as far as the viewer is concerned.