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I'm trying to do some blurred light dots and for doing this:

  1. I have made a particle emitter with a shiny particles
  2. I have decreased the focus distance of the camera

In the viewport I see the result that I want, but when I try to render I have obtained a different picture as you can see in the next 2 photos

Viewport

Rendeing

After the suggestion of Blunder my result is closer to the viewport, but it's like if where there is a small amount of light is not computed:

enter image description here

The spheres are made with the following node: enter image description here

bl4nk
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    Is this a Cycles render? – Blunder Jul 01 '21 at 15:53
  • Yes, I switched on Eevee and it works, may I ask you why this appens? And if there is any way to obtains the same result in Cycles? – bl4nk Jul 01 '21 at 15:55
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    Eevee fakes everything while Cycles calculates light rays and their bounces with physical precision. It's like in the real world when you take a photo in a low-light environment. There is noise in the image because of the little light that is reflected and it's diffused. For the render, a higher sample count and the denoiser can reduce noise. Or you could use more light and darken the image in the compositor. But this is again a fake ;-) – Blunder Jul 01 '21 at 16:26
  • I realise right now that the result is similar, but not the same, it's like if the particles with the smallest amount of light is not computed – bl4nk Jul 01 '21 at 16:32
  • How have you made these disc particles? Are they transparent shaded? And where comes the light from? I've just made a bunch of metallic spheres in the dark, area light behind the camera. It renders really fast and I can see them all. But there is a lot of this noise called "fireflies". – Blunder Jul 01 '21 at 17:46
  • I have made some spheres as you (I'll put the material) and I added a point of light behind the camera – bl4nk Jul 02 '21 at 13:26
  • Related or dupe: How to create Bokeh circles? – brockmann Jul 02 '21 at 13:49

1 Answers1

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The first suggestion was very helpful: Switch to Eevee for a better effect, also enable Bloom.

The last thing that made the trick is to change the focus of the camera and put it on an invisible object (a tv series logo in my case) in the middle of the scene. In this way I have obtained near and far particles as blurred lights dots, but the ones near to point of focus are computed as spheres with too many details.

I don't know if it's considered cheating, but for this last problem I added a plane and enabled it's collision option, putting it above the focus and scaling enough permitted to the particles to don't fall in the zone in which the focus is centered, and consequently loosing the effect i was looking for.

What I made is explained partially here: How to create Bokeh circles?

enter image description here

brockmann
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bl4nk
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