听第4段材料，回答第9至11题。
W：I like that picture you put up on the wall yesterday.
M：Oh，thank you.It’s a photograph that I took on my vacation last year.
W：You took it yourself? I don’t know you were a photographer.
M：Oh，yes，I've been taking pictures for years.
W：It sounds interesting. Do you have any more of your pictures here? And may I see them?
M：Yes，certainly. some of them are faces，just faces of people who I see when I'm walking around.
W：Do you let them know that you’re taking pictures of them?
M：I try not to.I don’t like pictures of people who pose for the camera. I like people who are going about their business without knowing the camera is there.
W：I suppose you need a lot of equipment. How many cameras do you have?
M：Well，I have a dozen of them，but I use two of them more than the others.