To understand this lights problem I was prepareв more reallife scene. It reproduces a kind of evening shot with lots of lights in windows or street lamps. In my scene it's just a boxes with shell and without upper face. In each of 2500 boxes there is a light in a random position. Total 2500 lights as in previous scene. In this case any trick with 1 plane with texture on it is unacceptable and we're really need to use all 2500 lights separately. Of course you can ask me: "Why we need to render all of them at once if we see only few of them?". Ok. We can render only few of them and it will be a lot quicker withour noise, BUT. But we're want to see the light from this "windows" on trees for example, cast shadows from it, see them in reflections of cars and so on. Again, if we have few shots, then cheating with on and off parts of the lights is super tricky and boring. I don't remind that if we're doing an animation this is not acceptable at all.
So at the picture we're see that our skylight is clean and AA is fine. But our lights are terrible noisy! Max Ray Depth-1 (no GI i think), PT-64, LSM-2, Passes-50.
