All you need to do is go into a deep underground cave (Cathedral Caverns) that is a lot cooler than outside and then come back out into ridiculous heat and humidity and try to take photographs. Cue spooky steamed up effects. No need for Photoshop at all!
P.S. We are back from a fabulous time in America (Alabama and Colorado) and there should be more craft related posts soon. Although I still have lots of holiday photo's to show you so you may have to put up with those for a while :)