Cecofuli,
You are going to write “corona the complete guide” ? 
Ehh… Maybe =)
One of the most parts I don’t like VRay is the color mapping. Especially the famous problem with sub-pixel mapping OFF
I’m looking for a good render in CPU (cause RAM amount problem on the GPU and plug-in support).
Corona is a good renderer but it’s have, as we can see, some problem too in the color mapping area 
Here another VIDEO where you can see better all different light sources: CoronaSun, Portals, Rectangular CoronaLight and Emitters.
Only Rectangular CoronaLight seems not to be affect by Exposure compensation (or very slightly)
ok, this is weird, MSI should not influence the result so much. I’ll need to take a look at it when I am sober.
Keymaster yes, I think the same. But it could be a good start to have the Exposition parameter MSI indipendent 
maybe in some nightly build?
Becous eI would like to use for some interior render with artificial lights and geometry emitters.
But without this option and the MSI corrected it is difficult or impossible to do.
Ok, after some test,t his is my conclusion:
if you want that Corona takes into account the Exposure compensation (with Emitters Geometry an Sun), you have to raise up the MSI up to 200/400.
Corona Lights are not so influenced by MSI. This is the only way how to do with A4.
Now my question: are there a big differences in terms of quality/errors between MSI: 10 (default) and up to 200/400?
the exposure is preset before rendering in each case?
Yes Keymaster I change it before the launch of the render!
I clean up the scene and I post soon!
ok, post it, this looks like easily fixable bug
See the attachments
01_Karaoke_Corona.rar (7.65 MB)
ok, I did some experimenting and thinking, and I concluded that the error is not in the way MSI interacts with exposure, but that it is set too low. MSI should be a parameter “how bright are the fireflies permitted to be”. But setting it to 10 classifies most of your scene as fireflies (because it is relatively hard scene, lots of indirect lighting). The problem does not happen with rectangular lights, because they make the scene easy (lots of direct lighting). Point the rectangular lights into the ceiling and you will get the same result.
Anyways, because the scene renders fine with high MSI, I think the best solution is to set the default MSI higher
Ahh, ok, now I understand.
But, from your point of view:
() what is the best setting for the MSI Default values? Because in my scene it was between 200/400.
() Are there disadvantages / advantages by using so high values?
Thanks
It might differ from scene to scene. If 200 works, use 200. I will test later to determine new default
Advantage of high MSI is less bias, disadvantage is more noise, it is simple
I did some test and with this scene. Corona is veeery slow compared to VRay. See the render.
() VRay: 1h with noise threshold 0.003 = PERFECT. I can in 30 min with noise threshold 0.005 and the noise is little more, but not too much. (BF+LC)
() Corona: 1h min. so much noise! (PT+HD)
Did I do some error?
can you share the scene? I want to test the it.
It’s in the attachment some post above. Ready to Corona. Just hit render
hd cache max records 100?
it is *1000