Hi Folks
This is my first posting so please be gentle with me
What Hollis_f said (who is a good mate of mine) is true. I was recently in Curacao (Dutch Antilles) and upon taking my Canon gear (20D + 100-400 L IS USM) out of the air-con'd room, immediate condensation all over the camera/lens (obviously worse on the glass components) was the result!
Initially I tried to fight nature by trying to clean the condensation off (Doh!), but when my brain engaged, I realised the answer was to just be patient and wait whilst the gear got acclimatised/acclimated!
A 10 minutes wait seemed to be the optimum (but that would likely depend on the level of humidity and how cold your room was!) but after that, there was no trace of any condensation at all. The very annoying thing was that every interesting bird species imaginable seemed to turn up - during the 10 minute wait
I also grabbed some rice which, in the absence of silica gel, was the most hygroscopic thing I could think of (and I wasn't exactly going to use salt!). You can imagine I got some very strange looks when I tried to explain what I needed the rice for!
Hope that helps
Didi