How do you know when a story is finished?
"I don't think a story is ever finished, but you do need to know when to stop. It could always continue, but you need to feel like you've exhausted the story (meaning you've done the most you can) and have something you can bring to the world."
How do you encourage people to act naturally in front of the camera?
"Some people are always natural but with others you need to spend time making them comfortable with someone standing in front of them with a big camera. I sometimes try to explain what I'm trying to achieve. Many times just explaining your intentions and who you are will break the ice. I also ask what makes them more comfortable, or where they want to be photographed. But most of the time saying what you would like to do works best."
What is the most challenging aspect of a documentary project that most people might not realise?
"The most challenging thing is getting permission and access to certain topics. For example, when I went to Libya in 2010 it took me more than a year to get a visa. Some places are really difficult to access with a camera, such as prisons and detention centres. You need a lot of patience and persistence."
Have people ever been upset after consenting to being photographed, and how do you handle those situations?
"Sometimes I take a photograph first because I know I won't get a chance to capture that moment again. But I always ask afterwards if it's OK. I'll show someone the image if they ask, and if they aren't happy I'll delete it. Yes, sometimes people aren't happy with the way they look but I haven't had any serious issues. It's more about aesthetics and people's expectations. I try to explain that reality is more important than keeping up appearances. If only we could be more truthful and transparent in general, life might be more pleasant."