A film about an eccentric early adopter of autobiographical filmmaking kicks off the Open City Documentary Festival tonight. Sam Klemke’s Time Machine, directed by Matthew Bate (who made the fabulous Shut Up Little Man! An Audio Misadventure) tells the story of how Klemke for 35 years has documented his own underachieving life – in end of year video diaries detailing his spiraling girth and roller coaster love life. It’s just one of many intelligent, thought provoking docs dominating the festival, whose 5th edition sees it expand to cinemas across London.

Since its inaugural year in 2011 the festival has grown four-fold in numbers, from 1,000 to 4,000, according to festival founder and director Michael Stewart:  “We’re trying to grow about 20% in terms of audience each year, up to the point where we have the right kind of audience.  We’re not in the business being a 100,000 person festival,” he says.

The festival maintains a principle of showing films which otherwise wouldn’t get distribution in Britain. Whilst the first year showed an overambitious 180 films, the festival has decreased the number of films, in order to ensure each one receives the attention it deserves, according to Stewart. University College London continues to fund about a third of the festival, but this year all screenings have shifted from the university’s lecture theatres to cinemas. The ICA, Bertha Dochouse, Regent Street and Picturehouse Central are among the venues, which Stewart hopes will draw a diverse crowd of doc lovers.

It remains to be seen whether the geographical expansion of the festival will detract from its feel: “How you build a festival in the middle of London and which is all over London but has a festival hub atmosphere is a challenge,” admits Stewart. “We’re working on that.”

Open City is also running a number of industry events, including a session on Wednesday, A Smart Portrait of London, on the data generated by digitization of our cities. The industry events also include a number of radio sessions, as well as making online docs for the likes of the Guardian, Vice and Dazed. According to Stewart, practitioners in London are hungry for such fare:  “What we have put on for industry has really expanded. We’ve got a whole week of events, doing things which people can’t get elsewhere. There are 100,000 people working in the digital film industry in London and they’re not served properly. They don’t all go to Sheffield by any means.”

Open City closes on Sunday evening with a moving personal doc from Scottish filmmaker Karen Guthrie, The Closer We Get, in which Guthrie returns home to look after her ailing mother and explores some painful family secrets.

Check out the Open City web site for a complete schedule.