The amazing work of a small Johannesburg audio-visual company that employs about 20 people was propelled onto the world stage as it delivered a half-dome stage for former US president Barack Obama during the annual Nelson Mandela memorial lecture.

Blackmotion Production, founded by entrepreneur and lighting designer Kagiso Moima wa Masimini, 39, was tasked with its biggest technical production work since its launch 13 years ago.

After having partnered with the Nelson Mandela Foundation, delivering technical production work for the past two lectures, Moima wa Masimini did not believe it when told at the beginning of the year that the lecture was going to be addressed by Obama.

"I did not believe it, in my head I was not ready; I thought I'd be able to creatively design something for Obama in the next 10 years. I didn't think it would be this soon," he says.

After roping in his friend Lefa Tsiane as project manager early this year and getting the services of veteran local lighting designer Tim Dunn, they, with others, went through 84 revised drawn plans.

The entire project included lighting, the stage, LED screens, seating and sound, with about 560 people involved.

The brief from the foundation was terse and to the point: "We are hosting Barack Obama this year and we will have 16 000 people in audience, and this will be broadcast live across the world."

Although some of the previous Madiba lectures were addressed by former US president Bill Clinton and former UN secretary-general Kofi Annan, Moima wa Masimini said Obama was the biggest name by far.

"I think with what's been going around, Barack Obama, with him being the first African-American president of the US, that just lifted the profile [of this year's lecture]."

Putting up the impressive half-dome structure alone took five full days, Moima wa Masimini says.

His highlight during the lecture was a firm handshake from Obama.

"It's such a humbling experience to get a former president of the US walk off stage, as you open the door for him, he takes your hand and says: 'good job'."

Nelson Mandela Foundation's CEO Sello Hatang says: "You can't deny the project was well-delivered, executed by a company that's black-owned . ever since I've worked with them, we have enjoyed nothing but efficiency and great production."