One of the first truths to be gleaned from Rob Henry's new film 'As Worlds Divide' is how little we know about the indigenuous Mentawai. 25 years after the Mentawais were 'discovered' and surfers filed like lemmings to those brilliant coral corners, the inhabitants of the islands are largely a mystery.

And I say this as someone who's got off a Mentawai charter boat many times to 'meet the locals'. Even stayed in the land camps to do the same. Yet Henry shows that Mentawai culture is more complex than can possibly be gleaned in a cursory visit, and there are also layers of politics that are equally hard to discern.

Henry's Indonesian story begins at Pit Stop Hill Resort in the northern reaches of the Mentawais. He's hired to film video and shoot photos of paying guests, yet he's captivated by 'Andy' a local Mentawaiian hired to work as a surf guide. In time, Henry quits his job at Pit Stop Hill and goes to live at a nearby coconut farming village, in essence to understand why many locals seem satisfied when they have so little.

It's here the anthropological journey begins.

Calling it an anthropological documentary may not appeal to everyone, yet it sure isn't a surf movie. That it's based in a region known for great waves is incidental, though if you too have got off the boat to 'meet the locals' then you'll be curious by what follows.

Like all good field researchers, Henry slowly gains the confidence of his new neighbours and is absorbed into their world. His gentle demeanour and willingness to assimilate appears the key to entry, and the doco is made all the more powerful by how often he rolls tape, including one-on-one talks where locals share their joys and their worries.

Many months into his visit - the doco is filmed over nine years - Henry learns how blanket policies imposed from distant Jakarta are displacing native Mentawai. Forced into government settlements where the children get schooling but where there's little employment, the familes are forced to seperate; many fathers see little of their children and native wisdom and lore is dying.

Henry moves deeper into the heartlands of the islands, ending up with a tribe who remain largely unaffected by government intrusion yet there's a melancholy resignation that their isolation can't last. That this generation of children will be the last to live off the forests. "We don't want to practice a different way of life," says one woman. "We want to stay here. We want to protect our cultural way of life."

Filmed over Henry’s nine years living amongst the Mentawai, 'As Worlds Divide' confronts the impacts commercialisation, forced displacement, and assimilation have had on the Mentawai people. Pan out and the story is one of globalisation smothering indigenuous cultures creating an unwanted homegeny, but it's also about how one of those threatened cultures is responding to the challenge.

'As Worlds Divide' film premiere to be tonight at Deakin Edge, Federation Square (Melbourne). Click here for tickets.