If you’ve been reading my posts here at DIY Photography for a while, you probably already know that I generally don’t spend too much time on some of the more technical aspects of photography. I’ve covered legal issues, written some fun reviews, and put some myths to rest, but I pretty much spend most of my time here howling at the moon. Okay– maybe not literally howling at the moon, but the opportunity to share whatever random thoughts have been bouncing around in my head a couple of times each week is a privilege I don’t take lightly– even when I’m ranting. I’ve decided that today’s going to be a little bit different. Today we’re geeking out and deciphering one of the greatest photographic mysteries of all time– your flash’s guide number.