Firefly cluster in cycles with high samples

Support Lighting and Rendering
1

How exactly can I remove these clusters of white specs that are appearing on this glossy shader (with a roughness of 0.14)? The lighting is just an HDR (Specifically openEXR), and I have some DOF (that’s why it is slightly blurred).

Here is the close-up photo:
http://i.imgbox.com/Wv6AK7Mi.png

I’ve tried removing caustics and filtering glossy, but neither of them help. In the compositor I’ve tried using the despeckle node, but it did not help. This is rendered at 50 samples and is in an animation rather than a still photo so I cannot just use photo-editing software to edit it out of the photo. Any help is appreciated :). I can post the blend file if someone needs it.

2

Here is a basic summary of what is happening:
I have a rough glossy shader with an HDR image, and I get these white dot clusters that won’t go away. Any ideas?

3

50 samples is not high… try rendering with 150 or 200 or so?

Also have you got Multiple Importance Sampling turned on on the world? you are lighting this from the world right?

4

I have tried turning Multiple Importance Sampling on and off in both the world and the material. And yes, the lighting is only from the HDR. I know there is a bright sun on the HDR which I think might be causing it, but I still don’t know how to remove it since it is unnatural.

Here is the same thing rendered at 10,000:
http://i.imgbox.com/iYjewjzk.png
It improved slightly, but it is still definitely there.

5

OK, I’ve pinpointed the problem. Here is the same thing without DOF:
http://i.imgbox.com/ymidUTPR.png
The bright white specs are reflections that when blurred with low samples, looks terrible. Does anyone have any ideas how to fix this without removing the cycles DOF?

6

You have specular highlights on a glossy object. That is perfectly normal.

If you don’t want them, change the lighting or change the material.

7

As Organic said, it is absolutely normal, that you have SPECULAR highlights on glossy surface.

if you don’t want them, then you can simply set Clamp to 1 or even lower.

8

Thank you for your help. Clamp was exactly what I needed. Setting it to 0.5 completely removed the specular highlights.

9

… plus it removed most of the lighting. In this particular case maybe it works, but you should avoid setting clamp lower than about 5.0 or 6.0, but best don’t clamp at all.

10

Clamp kills the dynamic range of your image.

11

OK, I understand. Like mentioned, I had no need for lighting in the scene; I only needed the reflections for the material. But in other cases I realize this would not work.