Sunshine Superman

Screened at last year's New York Film Festival and shortly to have its international premiere at Edinburgh Film Festival, Marah Strauch's soaring Sunshine Superman has at its centre Carl Boenish, who was diagnosed with polio as a child and went on to become recognised as the founder of BASE jumping. He comes across as fearless, starting out in movies doing the aerial cinematography for John Frankenheimer's The Gypsy Moths, with Deborah Kerr, Burt Lancaster and Gene Hackman.

Strauch's documentary is filled with light and air, keeping up a refreshing lack of cynicism. In interviews with Carl's wife, Jean, the film explores how the private man, the scholar of Christian Science and the pusher of boundaries influenced his environment. BASE stands for Building, Antenna, Span, and Earth.

The choice of Richard Wagner's Tristan And Isolde and Lohengrin to go with the visuals makes perfect sense. Breathtaking aerial footage shot by Boenish and his colleagues accompanies a glimpse into the development of the extreme sport, always close to the edge, head in the clouds. One scene shows him on a home-made construction, a fragile Harold Lloyd combination of a ladder and a bicycle seat, stretching out over a cliff, 3000 feet high, in Yosemite National Park in California, to get his footage of jumpers. It makes your head spin to watch it on the screen.

Strauch's debut feature at times takes on a surprising quality, with nothing really quite what it seems. Park Chief Ranger Bill Wendt, at Yosemite, says, "you don't have to dislike someone to take away their freedom." His appreciation is obvious and the complicated humanity shining through, a rare pleasure to watch.

Some of the private moments, Jean Boenish talks about, are reconstructed by Strauch with actors, such as a footrace on the couple's first date. Stronger evidence for their unusual bond are the interviews with friends and fellow jumpers who speak of their impressions that Jean "did not look like a skydiver," more like "a librarian" or "nun." Her derring-do clearly proved them wrong.

When I spoke with Marah in New York, she told me how Werner Herzog at his Rogue Film School taught her to metaphorically "pick locks and forge documents." She had watched early German mountain films by Arnold Fanck with Luis Trenker and Leni Riefenstahl but it is Romantic painters who set the tone of her film. Boenish becomes the lonely wanderer in spirit looking over the mountaintops. If he didn't wear a red jumpsuit, he could be straight out of a Caspar David Friedrich painting.

What is most astonishing about Sunshine Superman is how genuinely happy everybody looks. Leaping off buildings under construction, of course, is illegal and the film zooms in on various controversies from Houston, Texas in 1981 to mountain run-ins with rangers in Yosemite, up until the fateful day in July 1984 in Norway, when Carl's record breaking jump off the longest cliff face was not enough for him.

Carl believed that "everything happens for a reason," and although Strauch does not enter deeply into Boenish's faith as a Christian Scientist, she makes the audience wonder. Could the man who did not go to see a doctor for a broken leg and fearlessly pushed human dreams of flight to the limit, have done what he did without this belief?

Just last month, inside Yosemite National Park on May 16, 2015, BASE jumpers Dean Potter and Graham Hunt died in a wingsuit accident.

Sunshine Superman is currently in theatres in the US and will be screened at the Edinburgh International Film Festival.