Susan Sontag (all time fav of mine since Against Interpretation. She has a book On Photography:

"Most tourists feel compelled to put a camera between themselves and whatever is remarkable they encounter. Unsure of their reasons they take a picture. This gives shape to the experience: stop, take a photo and move on. The method especially appeals to people handicapped by a ruthless work ethic - Germans, Japanese and Americans. Using a camera appeases the anxiety which the work-driven feel about not working ... "
"Photographs are perhaps the most mysterious of all the objects that make up, and thicken, the environment we recognize as modern. Photographs really are experience captured, and the camera is the ideal arm of consciousness in its acquisitive mood."

My well beloved Roland Barthes too... Camera Lucida : Reflections on Photography