Alison Klayman first met world-renown artist and activist Ai Weiwei in China in 2008. The documentary she created over the following three years - "Ai Weiwei: Never Sorry" - tells of the pressure he came under from the government, house arrest and his eventual arrest for alleged "economic crimes." The film was awarded the Special Jury Prize at the 2012 Sundance Film Festival.

DW: How did you first meet Ai Weiwei?

Alison Klayman: I met him in 2008 through my room-mate, who was curating an exhibition of some of the 10,000 photos he took while he was in New York. My friend said it would be great if they had a video to accompany the exhibition, so we just struck an agreement that I would make the video but I would not be paid. Now I know how lucky I was, not just to meet him but also that he came to know me through me pointing a camera at him all the time. From the very beginning, we hit it off. I had so many questions for him.

How did he strike you initially?

As a very regal figure. He commanded the attention of everyone in a room. He could go from being very serious to being hilarious. He liked to joke around and that was very appealing, but he can also be intimidating. If there is something that he does not like, he will tell you. He is also willing to dive into political issues - and I'd never heard those kinds of comments from a Chinese citizen before. He was willing to be very critical and to do that on camera and on his blog. I asked him why he was not already in jail and he asked me the question back. In the end he said he was not in jail until he was. He told me that in 2008, a police officer had told him that if they wanted to get him, they could. It would not have to be a political reason, it could be any reason they wanted. And in the end, he was detained for economic reasons.

Did you ever feel threatened?

When I first met him, there were no surveillance cameras pointed at his front door, but when that happened he knew that he was making a choice, that he was crossing a line. His life was not his own. But it was ridiculous to put cameras on his front door because he was Tweeting all the time. He told me that they didn't need cameras because he was telling everyone what he was doing all day anyway. In the film, we went to a police station to complain when he had been assaulted by the police and that was a little intimidating, but I was an accredited foreign journalist and the worst that could happen was that I would be kicked out. But Weiwei and other Chinese citizens were taking a much bigger risk.

Why did you leave China?

I knew I would go to New York to edit the film when I had enough of a story, and enough footage to tell the story. In the summer of 2010, I went from fretting that I didn't have enough footage to knowing that I had too much. There was the art, his activism, his criticism of the official response to the Sichaun earthquake - I had more than 300 hours of video. So I decided that I was ready. Weiwei was also going to open a show at the Tate in London in October 2010 and I filmed his preparations for that, but it worked as a bookend for everything that had gone before. He was detained on April 3, 2011, and held for 81 days, although no one had any idea how long he was going to be held.

What is his status now?

The main issue is that the authorities continue to hold his passport, which means he is unable to leave the country. And for an internationally renowned artist, that's a big restriction.

Is he still well known in China?

He's not covered in the domestic press and his domestic social media presence was shut down in 2009, so it has been impossible for him to maintain a blogging presence. It's hard to remain famous when you can't reach people or when it is forbidden for others to write about you.

What is his philosophy?

He is passionate about some universal themes; free expression, transparency, the rule of law, respect for the voice of the individual and the individual's life. Those have not wavered and his core beliefs have not changed. After he was released, he told me that he would have to find a new way to play the game.

How has he changed?

When he first came out, he was much thinner and he said that was because he spent most of his time pacing. They gave him nothing to do, so he just paced in his cell. But his belly is back again now. One difference is that he is a person with a cause and a message, but pressure has been applied to his weak spot and knowing that is possible has changed him.

What are his plans?

I thought things would have changed by now, but there are still no indications of when his status will be altered. He does not want to live abroad, although if his life in China became impossible then I guess he would leave. He cares passionately about China and he wants to be relevant, but not to have the option to travel is a problem. It also raises so many questions; if he did travel abroad, would they let him back in? Since he was released, he has been making a lot of music, heavy metal albums, and by his own admission his voice is not very good. But what I admire most in him is that he is trying to find something with new possibilities so he can reach a Chinese audience.

Is he optimistic about the future?

I think he will always believe in the possible - and if you do that, you will always remain an optimist.

Filmmaker and journalist Alison Klayman, 29, is originally from Philadelphia but now divides her time between New York and Tokyo.

The interview was conducted by Julian Ryall in Tokyo