It is all physics and you need to remember that:
Fact 1. Warm air can absorb more water vapors than cold air.
Fact 2. When air saturated with water cools down, the excess water changes state to liquid and forms a fog or condensation on surfaces.
So here are come conclusions:
1. exposing a cold camera to warmer humid air launches condensation on all surfaces, that are colder than air - including circuits... [because surrounding humid air cools down at contact with cold surface and releases excess water...] (Solution: putting camera into seal-able plastic bag while in cold environment. Leave it in the bag until camera matches room temperature. The humid air will not get in contact with camera.)
2. changing camera environment from warm to cold is not safe. Imagine your camera sitting on your shelf - it is filled with air of same temperature and humidity as surrounding air in room. When you take it to cold environment, the camera body cools down to ambient temperature and so does the trapped humid air inside... - result is condensation inside body as colder air cannot retain water vapors. And weather-sealed cameras are no exception! (Solution: gradual temperature change - for example for couple of hours [if possible overnight] keep camera close to window where it is colder by 3-10 degrees [depending on window :) ] and detaching lens for 10-20 seconds if camera is weather-sealed, [to replace the humid air from inside with dryer air of new environment right after camera is brought to colder temperature])
3. hiding your camera under your jacket in winter (because you try to save some battery time) is very RISKY! Basically by hiding it under jacket you change the temperature and humidity of air surrounding your camera. Under jacket it is warm and humid as your body generates warmth and sweat so it is same as taking cold camera into warm and humid room... (Solution: camera sealed in plastic bag can be put under jacket [with cold air in the bag - as in conclusion.1]... but it is kind of silly to unwrap and wrap the camera in plastic before and after each shot... :) )
I hope it is understandable and it will help someone... -I usually make things look more complicated than they are... but it is, actually, pretty logic, isn't it...
and editing images :)...