I'm on vacation in Myrtle Beach. Yesterday was laying on the beach with the family, with my camera in my bag. A rain cloud appeared out of nowhere and rained for about 5 minutes. I threw a towel over my Tamrac bag. The inside of the bag stayed dry, but when I took my camera out about 10 minutes later, the lens was foggy. A few hours later I reached for the camera again and it was fine. This morning I took a walk on the beach with the intent of taking some sunrise shots. It was about 85 degrees and 90% humidity - you could cut it with a knife. When I took the lens cap off, the lens fogged up immediately. So my questions are, is it safe to wipe down the lens with a lens cloth when it fogs up, and is there anything I can do to prevent it?