How can you not love Henri Cartier-Bresson? The nonagenarian we see in “Henri Cartier-Bresson: The Impassioned Eye,” a documentary film directed by Heinz Butler, is alternately serene and spry, taciturn and pithy, but always charming – effortlessly charming. Virtually nothing happens in the film, but it is nonetheless a pleasure to spend an hour in such wonderful company.

The main action in “The Impassioned Eye” involves people – the audience included – looking at photographs Cartier-Bresson took during a career that began when, in 1931 at age 23, he first acquired a Leica. With breaks to work as an assistant to Jean Renoir on two films and to direct a few films himself, as well as 35 months in a prisoner-of-war camp during World War II, Cartier-Bresson produced an enormous number of photographs, many of which are among the best-known and most admired images of the 20th century. He stopped most of his photographic work in 1968 to return to his first love, drawing. We see many of his great pictures in the film and get to hear him comment of them.

“The joy of geometry. When you realize that everything is right,” is the first thing we hear – Cartier-Bresson speaking in French, then the English voice-over translation. The photographer, wearing hearing aids in both ears but otherwise remarkably intact, looks up from a print – a picture of a half-dozen men sitting and lying on the Boston Commons in 1947 – and looks at the camera with his cerulean eyes. He is pleased with the picture and pleased with himself for having taken it. Part of his charm is that there is no puffery in him, but also no false modesty. He knows the measure of his accomplishments.

What exactly does he mean by “geometry”? It has something to do with mathematics, because at several points later on he speaks approvingly of mathematics and its relationship to photography, painting, and music. Still, taking a picture is different than counting. Geometry has something to do with the abstract theories of Euclid and others, but also with “the way the different parts of something fit together in relation to each other,” to quote my dictionary. But this geometry is hardly a science.

“My passion has never been for photography itself, but for the possibility – by forgetting yourself – of capturing in a fraction of a second the emotion of a subject and the beauty of form,” Cartier-Bresson says discussing some other pictures. “There’s a natural geometry in what we see.”

The forgetting of the self and the “natural geometry” sound vaguely mystical, and we know Cartier-Bresson spent much of his career in the East,was married for 30 years to a woman who was a Javanese dancer, and admired Eugen Herrigel’s book “Zen in the Art of Archery.” Never didactic or loquacious, Cartier-Bresson speaks in gnomic axioms that are witty, profound, and just slightly beyond comprehension: “What counts is geometry and structure.Everything where it should be. To me geometry is the foundation.” And he adds, “Everybody has feeling.” Geometry, whatever its precise definition, is a “feeling,” and it is what makes his pictures great. “You see, you feel, and the surprised eye responds,” he says.

The photographer sits in his apartment overlooking the Tuilerie gardens in Paris talking to the camera about India, China, America, Mexico, Africa, Britain, and the many other places he has been. He recalls the people he met and photographed there,famous people like Gandhi, Nehru, Coco Chanel, Albert Camus, Matisse, Marilyn Monroe, and William Faulkner, but also anonymous whores and laborers and farmers. Cartier-Bresson came from a family of the haute bourgeoisie, but had a Whitman-like ability to relate to everyone he met on an equal plane.It is why his work is not only beautiful, but so humane.

There are other commentators on the pictures: the photographers Josef Koudelka, Elliott Erwitt, and Ferdinando Scianna; the important publisher of picture books, Robert Delpire; the actress Isabelle Huppert; and the overrated playwright Arthur Miller.

Mr. Koudelka was my favorite among the photographers.He is a Czech whose first extended project was photographing Gypsies in defiance of the communist regime. He made it to the West and membership in Magnum, the cooperative photographers’ agency of which Cartier-Bresson was one of the founders. Known for his refusal to do commercial projects (Magnum allows its members to turn down work they would prefer not to do), he got through difficult periods by sleeping on the floor of the Magnum offices.

Mr. Koudelka remembers the advice Cartier-Bresson gave him early on: “Take care of your eye.” He explains in his animated French that many photographers, when they become successful, let their eye get stale, and no longer see in fresh ways. He has worked hard with his mentor’s words in mind.

“Stories,” Mr. Koudelka says.”A good photo tells lots of stories. And different people tell different stories.A single picture, lots of stories.To me, that makes a good photograph. Henri’s best pictures are exactly like that.”

Ms. Huppert talks intelligently about her reactions to Cartier-Bresson’s pictures and then talks about the time he took her portrait. He took several shots, but one picture stood out.”When he sat across from me I had the feeling that he had seized on something in me of which I was unaware,” she says. “Something I would not discover. Probably I know myself pretty well, and what I look like in pictures. I’ve been photographed so much. Something completely unexpected happened with him. It was a moment of truth. Profoundly true.” And, in fact, his portrait gets past the beautiful movie actress to the soul of a real human being.

Henri Cartier-Bresson was known for being camera-shy, for refusing celebrity,and for traveling under a false name. He died August 2, 2004, at 95. We are fortunate he consented before then to be interviewed at length for this film, which was first released in Switzerland in 2003. In the last glimpse we have of him in “The Impassioned Eye,” he suddenly raises both hands, cocks his thumbs, and shoots his index fingers at the camera. “Pow!” he says. “Either you get it or you don’t.”

Opens January 13 at the Quad Cinema (34 W. 13th Street, between Fifth and Sixth Avenues, 212-255-8800).