Thanks Frank, but I had discribed this issue already in Ask Conitec (Static light, 7 sept.)
Now I have tested some more;


Shot at 2007-09-22

Here is the HiRes on for the light and the 'ceiling' left box is 8 quants and the 'ceiling' of the right box is 4 quants.

Has this also to do with the shadows?
I get a stange shadow when I move thw static light a little;


Shot at 2007-09-22
HiRes=on.


Shot at 2007-09-22
HiRes=off.

Another strange thing;


Shot at 2007-09-22

This is a model with cast=on but there should not be a shadow because the suncolor is set to 0,0,0.