I like to photograph Mt. Rainier’s waterfalls. If I am really lucky, I’ll get to shoot when the fog is trapped over the falls. Fog makes everything more interesting to me as a photographer.
Unfortunately, fog will usually fool your camera meter. The brightness of the fog (like snow) makes the camera think there’s more light than really exists, so it doesn’t allow enough exposure to properly render the scene. You can compensate for this by adding a stop and one half to your exposure. Most cameras have an exposure compensation dial that makes this easy or you can do it manually. In some cases you can add as little as one stop. Sometimes you may want two full stops. I suggest you bracket and experiment. Just remember to add some exposure when you shoot into the fog or your pictures will come out underexposed.