Using God rays makes part of the room to dark

My 3D Spin

I want to use god Rays in a room thats lit up by the sun and have the rays fall through
a window but part of the room gets to dark like it was night. I use Scene unly - cause
when you add any other light the effect of the rays and dust particles disapear. 
Anyone has any solution for this?

Paintbox

You could try if in Render settings -> tone mappings and decrease the value of F/Stop, this is the equivalent of letting more light in the lens on a real-world camera. Depending on your scene, this might be enough to get the result you want. You might need to decrease the god ray light, if the light becomes too bright in the picture.

My 3D Spin

Paintbox said:

You could try if in Render settings -> tone mappings and decrease the value of F/Stop, this is the equivalent of letting more light in the lens on a real-world camera. Depending on your scene, this might be enough to get the result you want. You might need to decrease the god ray light, if the light becomes too bright in the picture.

The F Stop only made it darker. I increased the ISO and that made it more lighter. 

Richard Haseltine

Lower f-stop and shutter speed shoudl be lighter, higher ISO is lighter. However, unlike a real camera there are no trade-offs (with a real camera lowering the f-stop decreases the depth of field, a slower shutter adds motion blur if things are moving, and a higher ISO adds noise) so it doesn't matter which you use.