Poison ivy. Over the years, I've had plenty of personal experience with the stuff, such that I know that I want nothing more to do with it. Luckily, when you use a camera to investigate the world around you, you have a little working distance between you and your subjects built in to the process. You don’t have to touch the vines. At the quantum level, it's well known that the act of measuring perturbs the system. I wonder, do the camera and photographer leave a trace even at the normal scale of human experience?
