Both intimate and expansive, “Free Solo” is a documentary beautifully calculated to literally take your breath away. And it does.

The film’s subject, Alex Honnold, is the foremost practitioner of free soloing, the art of climbing dizzyingly sheer rock faces with no ropes, no harnesses, just bare hands and dazzling determination and skill.

“There’s no margin for error; you have to do it perfectly,” one climber explains, comparing the endeavor to an Olympic sport where “if you don’t get the gold medal you are going to die.”

“Free Solo” opens with an arresting overhead shot, almost too unnerving to watch, of Honnold at work, his chalked hands finding crevices that don’t seem to exist, pulling off seeing-is- not-believing moves that are more astonishing than the most ambitious special effect.

When Honnold shocked the free soloing world by climbing Yosemite’s imposing 3,200-foot El Capitan, the New York Times made the event a front-page story and called it “one of the great athletic feats of any kind, ever.”

Directed by Elizabeth Chai Vasarhelyi and Jimmy Chin, “Free Solo” chronicles the ins and outs of that instantly legendary climb as well as a whole lot more.

On one hand, the documentary lets us in on how much went into the climb on a physical, psychological and emotional level, showing us how meticulously even the tiniest move is planned.

But “Free Solo” is also a surprisingly personal film, allowing us privileged glimpses of Honnold’s private life.

This includes the dynamics of his relationship with girlfriend Sanni McCandless and the question of whether the emotional connection romance entails is compatible with the kind of laser focus free soloing demands.

Vasarhelyi and Chin are ideal people to tell this story, and not only because they’ve already done another superb mountaineering film, 2015’s “Meru,” which was short-listed for the best documentary Oscar.

Chin has been an accomplished climber as well as a photographer and filmmaker, so he’s known Honnold for years and has the kind of rapport with the climber that makes the film’s candor and emotion possible.

Chin insisted his entire crew, including fellow cinematographers Clair Popkin and Mikey Schaefer, be experienced climbers, and one of the film’s most compelling aspects is how nervous these extremely knowledgeable folks were about Honnold’s safety.

The directors and crew worried that their presence might put undue pressure on Honnold, might lead to acts of what Chin characterizes as “Kodak courage.” More than that, verbalizing the unthinkable, no one wanted to be there shooting film if he made a mistake and died.

Honnold in person turns out to be smart and articulate with a mordant sense of humor and an off-beat streak, someone you would not pick out in a crowd. Aware of a distaste for vegetables, for instance, he systematically introduced them to his diet one at a time until he found ones that worked for him.

A perfectionist since he was a boy (“Good enough isn’t” was one of his mother’s favorite phrases), he found his gift for free solo early. One possible reason Honnold is so good at it, doctors hypothesized after giving him an MRI, is that his amygdala, the part of the brain that regulates fear, doesn’t react the way it does in most people.

“Free Solo” catches up with Honnold in the spring of 2016 when he is living in his van because he travels a lot, something that has hurt his romantic life, he tells a questioner.

But though he also says, “I will always choose climbing over a lady,” Honnold is soon “trending toward a girlfriend.”

That would be McCandless, who met him at a book signing and whose warm, incandescent personality seems an ideal match for the climber’s introverted demeanor.

El Capitan, which Honnold calls “the most impressive wall on Earth,” and which he’d climbed some 40 times with ropes, had been on the climber’s mind for eight years before he decided he would attempt to free solo it.

Vasarhelyi and Chin’s film follows two tracks. We first follow Honnold’s intense physical preparations for the climb, the way he goes over it almost inch by inch with fellow climber Tommy Caldwell and copes with delays caused by injuries.

“Free Solo” also sensitively tracks the ups and downs of Honnold’s relationship with McCandless and the worry that emotional entanglements are putting him off his game.

“FREE SOLO”

***

(PG-13, 1:37)