I have worked with the Estate of Yousuf Karsh for several years, and I edited text for the official Yousuf Karsh website, but I still hear stories about the shoots that I have never heard before. Tooling around today I found a comment from 2009 in an article on The Online Photographer, Mike Johnston's extensive photo blog, about Karsh's most recent book 'Regarding Heroes', from a reader who had attended the opening at the Art Institute of Chicago. Director and Curator for the Estate, Jerry Fielder, had related the story of Karsh's 1990 session with Mandela, and confirms this is what happened.

I personally never had the opportunity to meet Mr Karsh but it's easy to gather he was extremely charming and entertaining. The commenter, Ken Tanaka, put it so well, I hope he doesn't mind me lifting his comment.

"In 1990 Karsh was to photograph Nelson Mandela. Mandela arrived at Karsh's studio in Ottawa with only an hour of rest after his long trip from South Africa. Karsh was normally a master of establishing quick rapport with his sitters but he could see that Mandela was just plain exhasuted and that getting that "public mask" off would be very hard at that moment.

So Karsh decided to try telling Mandela a story to warm things up. He recounted a recent session in which he photographed the Pope. While chatting, he asked him, "How many people work at the Vatican?". The Pope considered the question for a moment, as if trying to formulate an accurate answer, and then replied, "About half.". For a moment Mandela's exhaustion and troubles lifted as he found the little story hilarious. Click! Karsh managed to capture that moment in this portrait."

This is one of the results.