Thomas Bena came to Martha’s Vineyard 21 years ago as a carpenter. Invited by a former teacher to help fix up an old barn, he fell in love with the island. His new trade allowed him to earn a good living and gave him the satisfaction of working with his hands.

But after a decade or so, Bena began to suffer a crisis of faith. Though working on giant new homes put money in his pocket, he couldn’t ignore the cynical attitude of developers who got rich building “McMansions” for seasonal visitors. The environmental and social costs were piling up, making him worry that the island’s unique way of life was being threatened.

Curious, concerned and inspired, Bena put down his tool belt and picked up a camera. His debut film, “One Big Home,” follows him as he tries to understand the implications of massive development on a small community. The film also focuses on his attempt, working with fellow citizens, to pass a bylaw that would limit the size of new homes. It will be shown at Waters Edge Cinema in Provincetown this weekend, and Bena will hold a Q and A at Saturday’s screening, which is a fund-raiser with pre- and post-film receptions.

Bena started shooting “One Big Home” in 2004, and it took him more than a decade to finish the project. For a long time, the passion was there, but Bena struggled to find the film’s central message and a tone that worked.

“At first, it was a Michael Moore style documentary,” he says. “I was sort of making fun of people and their choices. When I watched it, though, it felt kind of gross. I realized that I like films in which directors put themselves in them and ask really hard questions.”

Bena got some advice from Alan Berliner, known for his deeply personal documentaries. “Alan told me to make the film about just one thing,” Bena says, which got him thinking. “I realized that what I really wanted to talk about was the power of one individual, even someone with no civics experience, to make a change. Once I did that, I think it got a lot better.”

As much as it’s a story of questioning and resistance, “One Big Home” is at heart a homage to Martha’s Vineyard itself. Aerial shots of the marshes, sea, forests and dunes give a sense of how precious life on the island is — images that are all the more jarring when interrupted by a gravel-filled construction lot.

Over the years, Bena interviewed dozens of people. Some are developers, some are old-school hippies who came in search of a counterculture, and some are longtime residents, whose families have lived on Martha’s Vineyard for generations. He asks for perspective from a Wampanoag tribal member and a retired fisherman (Chris Murphy, who will be present at the Provincetown screenings). These conversations offer a sense of what can be lost in the throes of consumer culture. Taken together, they attempt to define what it means to have a home.

For people like Bena, community, love and tradition win out over square footage. Even so, he recognizes that change is inevitable, and the film steers clear of invective. When he interviews home owners, architects and builders, he doesn’t shy away from tough talk, but he lets his subjects speak for themselves, and he has a compassionate ear for those who are willing to share their point of view on camera.

A longtime film buff, Bena is also the founder and president of the Martha’s Vineyard Film Festival, now gearing up for its 19th season in March. He had some experience after college working in the television industry in California, but Bena says that curating the festival has been his true education in film.

“I’ve learned so much from visiting directors, especially listening to them talk about their films and how they did it,” he says. “We try to play films that spark discussion about issues we’re facing in our community. We also teach filmmaking to kids, and we go into schools and teach kids to think critically about what they’re watching.”

Since the release of “One Big Home,” Bena has traveled around the country with it, speaking about the impact of development on rural communities. He says that the debates after the film have been intensely gratifying.

“A lot of people want to know how they can do something similar in their communities,” he says. “If you look at the country today, people are hungry for a message of positive change.”

And even though rampant consumer culture isn’t likely to diminish any time soon, it’s a relief to see a film that focuses on what a community can change, rather than what it can’t.