[milosh]

The problem you are talking about is condensation, which happens because of the difference in temperature. In your case, the camera and the body were cooled down and when the warm air outside came in touch with these cold surfaces, the moisture from the air condensed. It the same thing that happens when you blow air from your mouth onto a cold window glass. The solution is to wait for the temperatures to normalize and the condensation to disappear. If you left your camera in the bag, maybe it would help, maybe it wouldn't. If the whole bag and it contents was cooled down so much, it would happen again. But a bag certainly helps to keep the camera protected from sudden temp. changes.