Oh a tip on thin haze, use Volumetric light.  Set density to less than 20% and Quality to 4-7%.  Gives a great haze without killing your rendering times too badly or overwhelming the picture.  AND it's usually quite consistant throughout the image doing a lot of ambient like functions without giving the "glowing item" effect.

Dont' forget, you can use it from under the tree, but don't let branches obstruct what you really want to show.

mdb