More often than not I try to wander in the city streets taking photos of strangers. Interactions with total strangers could be easy if you use the proper communication skills but most of the time they are not. Here are my thoughts on shooting people you don't know.
Fear and hesitation
Fear is the number one inhibitor photographers face. Many times I missed a shot because I hesitated fearing that the person will be mad or will start shouting at me in the street. I just walked away missing a great shot. I am sure you have faced similar feeling or else you are not reading this post. The remedy is to start challenging yourself mentally and to start gradually have confidence in your practice. If you are not shooting a murder or a mafia member in an exchange there is really no danger. So stay around, walk around, and wait until you have eye contact with your subject then nod as if requesting permission to shoot. Do this at the same time as you show your DSLR as a sign that you are asking to shoot and that you know what you are doing.
The hidden complement
Most people are not happy being photographed. Others take it as a compliment that you have noticed them, that they are pretty and that you want to take their picture. It is a social behavior that instinctively open doors for you and brings opportunities to shoot.
I was wandering around Rome last months and a pretty girl came to me with a brochure about a new supermarket that has opened across the street of my hotel. I immediately engaged with her knowing that I will be taking permission to shoot her. So I started asking questions about the address and the nature of the market until I found the right moment to say: "I will definitely go there tonight if you let me take your photographe." She immediately nodded with a big smile as if she was flattered about me noticing her beauty.
So, the secret is to wait, smile, wait again for them to smile back, show your camera, wait again for them to nod and take the shot.
Don't act as a paparazzi. Be genuine and act professionally
Most people hate it when a stranger points this/her camera at their faces without any introduction and then walk away. Treating everything as a subject is the most disrespectful thing you can do as a photographer. I've seen tourist shooting homeless people, people shooting beggars on the streets, or shooting couples kissing in the park, etc. I tell you if you don't make a rapport with the subject before and after you take the shot, this isn't ethical photography and you should find a job as a paparazzi for some yellow celebrity magazine.
The import thing is being respectful and genuine in your approach. People will tell immediately if you are and they will immediately accept. The more you practice, the calmer you’ll become and the more authenticity you project. Tell them why you are shooting them and where the photo will be posted. Give them your business card and ask them to email you so you can send them the result.
Well it depends! Most of the time I am on AV with a preset ISO depending of the time of day and shade settings. However, there is nothing wrong with being on the P dial. Whatever you do however, don't use flash. Flash is intrusive and may ruin your chance to get the shot. People tend to be intimidated by long lenses and flash. Try to avoid those two as much as possible.
Be cool, friendly, genuine and professional in your approach. Smile all the time and enjoy yourself. Shooting strangers is a great way to build relationships and get to know people and cities and off course a great opportunity to tell a story with your photographs.