DoF like "boiling", bad quality even at 1500 samples


I am surprised, what is this?? I am trying to render a simple cable that goes in focus, but even at 1500 samples and with the denoiser, there’s this really nasty noise that looks like if it’s “boiling”. I also tried with the better denoiser from K-Cycles, but no way to get rid of this… Any tips?



Are you using animated seed?

See if disabling that helps.

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Thanks for your response!
I didn’t even know this parameter, but it’s already deactivated in this project anyway

hmm, DOF is a noisy operation. Any chance you could use EEVEE for this shot? That DOF is a lot cleaner, not perfect, but pretty good:

Also, since it renders so much faster, you can render off tests much much quicker than waiting for cycles.

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Hey! Unfortunately Evee does really look fake, the light… my models… the textures … I have a good RTX and I prefer to wait to have better renders.

Is there any technique to improve the quaility of DoF animation renders in Cycles?? I am surprised the quality is so bad with something so simple as DoF, and so important for the cinematic renders

I took away all the Bump strength in the material’s Normal channel, and it almost corrected it, so it seems the DoF cannot deal with Bump maps

Try carefully clamping your direct lighting.
You could have some very strong specular on these bumpy materials that creates even more fireflies.

Although it depends on the scene, I don’t think 1500 samples is enough for animation. You test with at least 5000 samples. Additionally you can try OptiX temporal denoiser for animation in Blender 3.1. It has no user interface and you should follow the instructions in the following link:

It doesn’t do magic with the results either, but at least it gives a little better results when it comes to frame-to-frame stability.

Would it be possible for you to share the scene for testing? No problem if you can’t, I’m just curious.

@YAFU Thanks for your response!
5000 samples??? Auch!! … I am using K-Cycles (with it’s powerful denoiser) and some of my animations look really good with only 128 samples … I have a RTX3090 and it already takes a long time for short animations … If would put 5.000 samples … I would have to wait an eternity!!

Thanks a lot also for the links to the OptiX stuff, sounds complicated, but I will try it.

Anyway… as I said, once I set the Normal Bump Strength to 0, the DoF looked pretty clean.

I understand that K-Cycles has a temporal denoiser feature available.

If you could share a .blend scene to show the problem to developers, you could report this in the bug tracker so developers can decide if it’s normal for materials containing bump node to be more unstable for animation.

YIKES!! 5,000 samples?

I do Eevee animations at 20 samples. It is not photorealistic, but it’s good enough.

The eye is easily tricked when things move.

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Yep, we’re talking about Cycles. When we didn’t have AI denosier maybe samples above 15000 were needed for animation. Now that was hard.
AI denoisers and Adaptive Sampling has made things more bearable.

Anyway as I said before, it would be nice to know what developers think about DoF and bump node.

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