Here’s what many people noted first about Frederick Wiseman’s new documentary called “Belfast, Maine”: length.

“Four hours?” said one person who hadn’t seen the film but heard it was long. “That can’t be geared toward the common Joe. Seems like a half-hour might have been enough.”

Even at a reception that preceded the Maine premiere of the film Friday night at the Colonial Theatre in Belfast, the hum was about sitting in a cold movie house for four wicked long hours. It was as if people were preparing for a marathon.

Indeed, Wiseman’s portrait of Belfast, which has been well-received at film festivals in England, Scotland, Canada and the Netherlands, is a marathon of sorts. But the length — four hours and eight minutes — is only one aspect of what makes this documentary take up so much space.

First of all, there is the vastness of Wiseman’s canvas. The camera stops in one place, then pops over to another — from lobster boat to fish factory to church service to skateboarders to a flower design class to MBNA and the sardine factory. We watch donuts being made, clothes being pressed, a judge doling out fines, cars moving down the street, and houses sitting silently on the roadside. Then more cars. More houses. The ocean. Trees.

For four hours. And eight minutes.

But rather than call the movie long, it seems more accurate to call it demanding. This is not Norman Rockwell or Hollywood. You can’t just kick back, take a load off and smile. Quite the contrary. Wiseman wants your eyes and ears, smiles and scowls, head and heart at work here. Work, after all, is a recurring theme in Wiseman’s 31-film, 30-plus-year career. Anything less than your full attention and you might get stuck calling “Belfast” a long, albeit elegant, meditation, and then go buy a ticket for “Pokemon.”

On a critical level, however, Wiseman’s work moves beyond meditation and into the realm of deliberate scrutiny. The details are brutal, dramatic, comedic, poetic and constant. While some segments of “Belfast, Maine” may rightfully be charged with being ponderous, the film is hardly aimless or glib. Rather, it shows life in a rural community on the coast of Maine, where the ocean, the land and all their products weave together a human patchwork of revelations.

Still, you might ask what could be so lengthily important about Belfast, which takes less than five minutes to drive through? The question is a good one, and while the answer is writ large in the imagery of Wiseman’s screen, it can also be elusive.

The rush of images takes on the rigor of an epic poem, telling the poet’s story minutely and fearlessly. Forget time. Forget balance. Time and again, Wiseman has said he doesn’t believe in objectivity. This is his view of Belfast, not the department of tourism’s.

This is also not a history of Belfast. There’s no voice that tells you what’s going on, what went on in the past, who you are seeing or what you should take away from, say, a scene in which a social worker and client discuss the abuses of an alcoholic father. Wiseman may be your silent guide, but you have to draw your own conclusions — perhaps something about the spoils of child abuse as well as the determination of a daughter to redeem a parent despite his dangerous flaws.

There are moments in “Belfast” that are difficult to watch — a fox being skinned for its fur, a coyote caught in a trap and then shot point blank by a trapper, for instance. You’re tempted in those moments to turn away in the same way that you might in a horror film.

But then the camera turns its gaze to a nurse ministering to an old man who can no longer care for himself, or a state worker interviewing a stroke victim who can’t meet the payments for his medication. Or doctors in the emergency room, a cast in rehearsal for “Death of a Salesman,” or Neil Welliver, the artist, in his studio. These scenes show Belfast — or more broadly Americans — at their most compassionate, creative, understanding and engaged.

Nature, which serves as the backdrop, plays no small part in “Belfast.” Wiseman lingers generously on the land and sea, their quiet beauty and their bounties.

You may think “Belfast” is boring, and if you do, then it’s “boring” in the same glorious way as Sherwood Anderson’s “Winesburg, Ohio” and Walt Whitman’s “Leaves of Grass.” These chroniclers are among the most insightful in our national literature because they examine and reveal the lives of the “common Joe” and the shortcomings of the American Dream. With “Belfast,” Wiseman carves a spot for himself in their company.

The clearest clue to the essence of Wiseman’s work comes toward the end of the film, in a high school classroom where an English teacher is lecturing on Herman Melville’s “Moby Dick.”

“It’s an epic and it’s a tragedy and it’s also a book about whaling,” the teacher says. Eventually he adds that the common man is as fit a subject for drama as is a king.

In “Belfast, Maine,” Wiseman takes a Melvillean view of American life.

“Belfast, Maine” will be showing at the Colonial Theatre in Belfast for the next two weeks. For times and dates, call 338-1930. The documentary also will air on public television Feb. 4.