Reducing Grainy Lighting Effect?

[Spectralis]

Thanks for that tip. I'll experiment over the weekend and see if it helps.

[bepeg4d]

Hi,
I have seen your test. In general, in my experience, with emitters you need more sampling than with HDR or physical sun. And with IES light you need some more sampling to clear up compared to normal emitters.
Which IES file are you using?
Here is a good collection shared by Vinz some time ago:
http://render.otoy.com/forum/viewtopic. ... IES#p52161
Alternatively, you can try with a geometric spot emitter that in general is more easy to clean up compared with IES light:
http://render.otoy.com/forum/viewtopic. ... 5&start=10
About coherent ratio, if the value is too high, you can have a different flickering effect if you have not enough sampling, but not a grainy effect like this one. In the animation section is possible to override the current settings and choose a different sampling and coherent ratio level, in this way you can easily make some quick test for finding the correct setting for you:

ciao beppe

[larsmidnatt]

About coherent ratio, if the value is too high, you can have a different flickering effect if you have not enough sampling, but not a grainy effect like this one.
ciao beppe

that is true, it is more like a flicker now that you say it.

thanks for the tips.

[Spectralis]

I think the grainy light problem was due to having hot pixel removal set at about 0.5 rather than at 0. I must have changed the setting at some point. Setting it back to 0 almost doubles the render time but on a similar animation that I rendered the graininess wasn't a problem. Thanks for all the help and advice. Once I've finished these renders I'll spend some time experimenting with IES files and spotlights to get more experience using them.