In 1966, Thomas Hoepker was sent to photograph the world heavyweight champion. He reveals what it was like to shadow the mercurial boxing star in this video, the second of BBC Culture’s Through the Lens series.

In 1966, working for Germany’s Stern magazine, Thomas Hoepker was asked to photograph Muhammad Ali. Hoepker flew to meet Ali in London, and later in the year to the US. He followed the boxing star for days, capturing a range of poses – and moods.

“You could not anticipate anything – he was a surprise every day,” says Hoepker in this video, the second of BBC Culture’s Through the Lens series marking the 70th anniversary of Magnum Photos. “He could be a different person from one moment to another.”

During that shoot, Hoepker captured what he feels to be one of his greatest shots – an iconic image of the world boxing champion showing off his right fist. “I had two pictures, and these were the best pictures I ever took of him.”

Hoepker became a full member of Magnum in 1989. Here, he talks about taking that iconic shot – and more intimate images of Ali.

If you would like to comment on this story or anything else you have seen on BBC Culture, head over to our Facebook page or message us on Twitter.

And if you liked this story, sign up for the weekly bbc.com features newsletter, called “If You Only Read 6 Things This Week”. A handpicked selection of stories from BBC Future, Earth, Culture, Capital and Travel, delivered to your inbox every Friday.

Around the BBC