Sometimes when I'm taking a picture, I enjoy watching people cover their faces or suddenly turn away. Occasionally people react so violently that they actually trip over themselves, or lurch into poles, buildings, or other obstructions. It's not like I'm a sadist or anything-- I just enjoy that moment of unfalsifiable frisson between shooter and subject. It's real. Really real. In some ways, much more real than the faces that people present when they don't turn away. Allow me to illustrate with two examples: a man throwing up the deuces at me on Nostrand Avenue, and a boy talking on a cellphone in front of Luis TV Repair. In both cases, the subjects noticed me before I started shooting-- so I lost the explosive moment of recognition, the "degree zero", if you catch my drift. Instead, in those shots, you see something else-- the face that people present to the world when they know someone else is looking. That can be interesting too-- but it's at a degree removed from truth.