banding in spotlight

[Dune]

What can be the problem here? Banding in the spotlight. Everything default, except the beam width.

[Hannes]

Hard to tell. Sometimes JPGs have this kind of banding, but I guess this is the pure output? Does PNG have some sort of compression?

[Dune]

Nope, that's why I posted as png. It's already in the tif. But I think I know the culprit; I had glow in atmo checked and that causes the banding. Without, it lights the mist, but without the banding. Strange (bug?) but it's partially solved anyway. Thanks for your reply!

[WAS]

Glow in atmosphere is a beta, this may be the sort of results Matt is after for improvement. 

[Dune]

I don't mean the experimental atmo bloom, but the ordinary glow in atmo in the lighting tabs. Same as in the sun.