Zdepth for basic distance fog

#1

Sorry for the noob question, but I searched and tried how to make a simple distance fog over a beauty pass in fusion using a zdepth pass, without success.
In photoshop it is very straightforward, you just put the zdepth pass on top of the beauty pass in screen mode and voila.

#2

you could do the same in fusion

use a merge to put your Zdepth pass over your beauty (use the “apply mode” screen or “normal” with the alpha gain set to 0)

or you could use a fog node

or you could use the zPass as mask in a grading node (colorcorrect or brightness/contrast)