By Adam Blenford
BBC News, London
Vladimir Putin is many things: former KGB agent, confident world leader and keen judo player to name but three.
His role as a saviour of experimental photography is less well known.
The congress hopes to convert people to Lomography
Yet a bizarre-sounding meeting in 1995 between Mr Putin and a group of Austrian photography experimentalists today underpins a growing photographic movement that occupies the narrow space between the worlds of art and commerce.
Then deputy mayor of St Petersburg, the man who would soon be Russian president gave an audience to the Austrians to hear their pleas.
They had recently started selling refurbished Soviet-era cameras from the Leningrad Optics and Mechanics Association (Lomo, in Russian) to enthusiasts around the world.
Business was growing, but Lomo wanted out of the deal. The Austrians needed Mayor Putin to bail them out. They succeeded.
Lomo got a tax break, Lomo's Director Ilya Klebanov eventually became a deputy prime minister, and the Austrian company, the Lomographic Society, stayed in business.
Today, Lomography - motto: "Don't think, just shoot" - has an estimated one million followers around the world.
These devotees, or Lomographers, as they call each other, use old-fashioned "analogue" cameras to make photographs, or Lomographs, that seem a world away from the crisp, under-saturated images produced by many modern digital cameras.
By contrast, Lomo images are a swish of soft focus and vibrant colours, all captured on film and developed in a lab. Just like the old days.
Except it's not just like the old days.
With an active online community that uploads 6,000-10,000 pictures each day, and 500,000 Lomographers around the world who receive regular e-mail newsletters from the Lomographic Society, this is a thoroughly modern twist on an old-fashioned pursuit.
For the past week the Lomographic Society, now a highly-profitable worldwide enterprise which controls the entire world of Lomo from the cameras on sale to the online communities where the pictures are shared, has been holding a grand-sounding meeting in the heart of London.
Some 250 people from around the world, plus 500 more from the UK, have taken part in the Lomography World Congress.
The centrepiece of this week's London event is a giant snaking wall of some 100,000 Lomographs that fills much of Trafalgar Square, one of the world's great public places.
Lomographers have been fanning out across the capital, clicking their way through reams of film and surprising passers-by.
On a morning Lomo-walk eastwards along London's Regents Canal, the assembled Lomographers make an eclectic bunch: it's not too often you see a Taiwanese fashion director taking pictures of graffiti alongside a 52-year-old office worker from England's Isle of Wight.
American Brittany Diliberto, 21, has Lomo to thank for her stroll along the canal.
Aged 17, she won an online Lomo competition that gave her a ticket to Beijing. Another prize-winning performance there paid for her trip to London.
"I've made tons of friends through Lomo from all around the world, and it's inspiring being around people who are very creative and spontaneous," she says.
Gareth Wane, 27, from Manchester, England, has been a Lomographer since 1999.
He admits to being somewhat baffled by the "science" of traditional photography, with its emphasis on shutter speeds, apertures and composition, but instead carries his trusty, battered Lomo LC-A everywhere he goes.
"It feels like a fairytale sometimes," he says of the life of a Lomographer.
"It's not all about having the biggest lenses or the latest equipment. We just like walking around and taking photos."
And while some might sniff at the apparent crudity of the Lomo's images, the worlds of art and design certainly take the little cameras seriously.
Ever-increasing demand from the art world was why the very first Lomographers abandoned plans for careers in the law and in politics to set up the Lomographic Society in the first place, says Wolfgang Stranzinger, one of the original gang.
Lomographers: an eclectic bunch bound by their common passion
"We were going to stop after a final exhibition in 1994," he says.
"We showed Lomo images of New York in a gallery in Moscow and Lomo images of Moscow in a gallery in New York.
"The response from the art world and the media was immediate and immense. So we did a deal with the factory in Russia and went professional."
Today the company markets 20 kinds of cameras and has "improved" many of the old Russian designs, including that of its flagship LC-A, the original Lomo, now made in China and called the LC-A+.
An ever-growing band of Lomgraphers are willing to pay some £199 ($400) for the LC-A+, a 10-fold price increase since Mr Stranzinger and friends first found an old Soviet model in a Prague second-hand shop.
When the Austrians met Vladimir Putin back in 1995, they convinced the future president that keeping the Lomo factory in business would be good for St Petersburg.
Mr Putin certainly remembers old friends: in 2002 he reportedly sang the praises of Lomo cameras while meeting the Austrian president in Vienna.
With the Russian leader coming to the end of his time in office, perhaps the movement can expect a new, VIP Lomographer at its next World Congress.