I would like to darken the game rendering so that I can display menus. Is there way to do this?
When your game menus come up, display a UMG and inside the UMG draw a box across the screen and set it’s opacity to 0.5 or whatever you want it at. 
I added a border to the menu that darkens the screen which does work. But I would still like to be able to disable the auto-exposure and set the exposure manually.