Quote -  Either in menu Render -> Post render options or in the render window title bar, a small black and white circle.

I have some doubts about auto-exposure. Normally this compensates lighting defficiencies (turning too dark images into more illuminated ones and vice-versa).

Hi -

Artur, if  "doubts about..."  means being skeptical to the usefulness, I agree :-) That's why I always turn it off for starters.
The same goes for "Enable wind" in the atmosphere editor, wind may play with some Vue plants in an unexpected manner ("depending on..." many variables). You can always turn it on if you need this effect.