Cameras have an odd psychological effect on me. They have a way of heightening one form of reality, while diminishing others. With my camera in hand, I'm singularly focused on creating the perfect image — one with the potential to entertain, enlighten, inform, or influence those who view it. When I'm on assignment, everything in front of me is filtered through my eyes as if it were already a photograph. Realtime is no longer time at all, but a series of contact sheets from which I'm choosing the images I want to preserve. The result is that non-photographic impulses fail to trigger proper cognition and, subsequently, adequate defenses. This is what I call "the mythical invisible shield." And this article discusses how to use it to your advantage.