Quote from : Camera Lucida: Reflections on Photography Book

I imagine that the essential gesture of the Operator is to surprise something or someone (through the little hole in the camera), and that this gesture is therefore perfect when it is performed unbeknownst to the subject being photographed. From this gesture derive all photographs whose principle (or better whose alibi) is “shock”; for the photographic “shock” consists less in traumatizing than in revealing what was so well hidden that the actor himself was unaware or unconscious of it.