Originally Posted by carregwen

It is tricky. I think it's really important to show people you are not a threat to them, after all, you are a stranger - you could be anyone. It sometimes works to just start talking to them first, and quite often they will ask you about the camera and that gives you a lead-in. I find it often helps to say 'may I take your portrait', rather than 'may I take a picture of you'. I know it sounds pretentious, but people do like to be flattered. It also helps to explain why you are taking the shot, and what it may be used for. After all, some people (say a couple) may be having an affair...