Seal the camera in a dry bag or plastic bag while you're still outside, then leave it sealed until it has warmed gradually. Condensation forms when warm moist cabin air meets cold camera and lens surfaces, and it can appear inside the equipment as well as on it. Depending on the temperature difference and the size of the gear, warming can take an hour or more.
The mistakes that cause the damage are opening the bag straight away, taking the lens off, or plugging in a damp camera to charge. Resist all three.
This catches more people than the cold does. Condensation is often the bigger practical problem on an Antarctic trip, and it's entirely preventable with one bag and some patience.
Practical version of the routine: bag it on deck before you go in, put it somewhere out of the way, and don't touch it until you've had lunch.