This is a subject that may be a little off beat, but I would be curious if anyone has some ideas that might help.
My topside camera is a Nikon N80. Last year on a cruise, I had severe problems with the lens (front and back), mirror, viewfinder etc. fogging up when I left my stateroom on a cruise in the southern caribbean. It took forever to clear up.
I'm expecting similar results with my Olympus digicam when it is not housed. (hopefully the gel packs in the housing will prevent this).
I have heard that preheating the equipment with a hair dryer (not sure if this advise was tongue-in-cheek) may help.
Any ideas would be greatly appreciated.