Originally posted by MarkJerling Not sure what can be done to counter this, ...
One needs to let the camera assume the same (warmer) temperature as the humid air before exposing it to the humid air. For instance, putting the camera into an airtight bag, and letting it acclimatise (i.e., reach the same temperature) before removing it from the bag will prevent condensation.
Some camera bags may sufficiently prevent moisture exchange to support the same idea. In that case, one could leave the camera in the bag for a while outside, until it had a chance to warm up.
BTW, taking a camera that has been exposed to warm humid air into a cold room can also cause condensation. Again, the recommendation is to at least leave the camera in the bag for a while so that it can assume room temperature in a gradual manner.