I was out in the Swedish countryside last week and decided to try a star trail shot. I set up the camera to just keep firing 30 second exposures until the battery ran out.

The next morning I discovered that the camera lens quickly fogged over once the temperatures dropped, leaving 95% of the shots unusable. That project was quickly scrapped, and I left the camera with the lens off for half the day to make sure it dried out properly.

I'm sure some of you have run into this before. How do you get around it?