How to get extreme hard edges on FogMaterials?

Godot Version

4.2.x

Question

Hi, I love the way that emission works with volumetric fog. I would like to have an emitting object (for example a torch with a emitting end) behind a “solid” box of volumetric fog.

When I set Edge Fade to zero, the FogVolume still has faded edges (and there is a minor strobing efffect). How would I get a hard edge?

Basically I am trying to get a faint glow of an object through another, as if a half-transparent green plastic overlay is placed over a TV screen and a bright object on the screen is half shining through still.

Thanks for any suggestions