not sure if this has been dealt with here before - but last winter i found my waterproof casing fogged a lot, especially in the super cold.... or damper days at breck etc...
This is will be due to me having had the camera in my pocket (warmer) then bring it out to mount on my helmet, but it would also fog when on my helmet mount.
My plan is to just not use the water proof housing when skiing, to allow it to breath etc.... and to have some airflow inside the case.
Anyone else had fogging probs? Tips to stop it happening?