Magnum Photos veteran Eve Arnold with Marilyn Monroe on the set of The Misfits, 1961 (Photo: Eve Arnold/Magnum Photos)

Susan Meiselas, a veteran of Magnum Photos whose pictures you'd probably recognize even if her name seems unfamiliar, recently told me something startling about the original reception of her 1991 documentary, Pictures from a Revolution. Now playing at Lincoln Center as part of a month-long 60th anniversary tribute to the agency, Pictures follows Meiselas as she returns to Nicaragua 10 years after having photographed the Sandinista revolution; her images from that conflict became iconic as the best Magnum photographs do, combining a fearless willingness to work in the midst of combat with a certain stark visual grace. The film (co-directed with Richard P. Rogers and Alfred Guzzetti) supplements Meiselas' powerful images with the stories of her original subjects, who speak to her poignantly and candidly about their betrayed hopes and difficult lives.

But when the film came out, Meiselas told me, there were a number of people who didn't want the photographs challenged. "They wanted the photographs to be fixed in just an aesthetic, formal sense," she said, "and they didn't want to know the people particularly or hear their voices or know what their struggles were."

The debate Meiselas' documentary sparked in 1991 is still relevant today, and in that sense the Lincoln Center program seems particularly provocative. The subjects and approaches of the documentaries being shown could hardly be more diverse; included in the program are films about Magnum's history; about Marilyn Monroe and her relationship with the Magnum photographer Eve Arnold; about ordinary women in Normandy who fillet fish for a living; about countries including China, Cambodia and England. But even if most Magnum photographers have at one time or another experimented with film, there remains some tension in the very idea of a cinematic retrospective for a photographic agency: Aren't the pictures enough?

Magnum was founded in 1947 by four photojournalists: Robert Capa, Henri Cartier-Bresson, George Rodgers and Chim (a k a David Seymour, whose photographs are currently on view at the International Center of Photography). Having taken pictures during the Spanish Civil War and World War II -- pictures that still define those conflicts -- they went on to make an art of the photo-essay, finding ways to tell a story through still images alone. Over the years Magnum's photographers have shot the world's major political upheavals, the most intriguing or intimidating leaders and world figures, as well as producing commercial and more personal work. While the photo-essay died as a popular form during the '70s, it is, in a sense, being resurrected today on the Internet with collaborations like the one between Magnum and Slate, whose Magnum in Motion features allow the cooperative's photographers to build mini-documentaries using photographs and soundtracks.

Nicaraguan youths practice throwing contact bombs in Susan Meiselas' documentary Pictures From a Revolution (Photo: Susan Meiselas/Magnum Photos)

The Magnum mystique is hard to ignore in the documentaries at Lincoln Center. These films exemplify (and in some cases directly address) the sense that Magnum has of itself -- one that probably wouldn't be denied by anyone who cares about photojournalism -- as a kind of 20th-century Round Table. Magnum's photographer-knights, who each represent a formidable alloy of artist and soldier, clearly feel imbued with a nobility of purpose and are committed to protecting commonly-held values. The fact that passionate disagreements tend to arise between these strong personalities (Cartier-Bresson, for instance, criticizes Elliott Erwitt for taking on commercial work, while others point out that the income from such work has saved Magnum from extinction more than once) only adds to the sense that they're part of a close family.

Elsewhere in the series, the three-part documentary The Magnum Story, first released in 1989, outlines how that moral authority was first won and later questioned by Magnum's own photographers. By 1959, Erwitt took his famous shot of Nixon poking Khrushchev in the chest, and the image was used in Nixon's presidential campaign to show how tough he was on Soviets. In the documentary, Erwitt's ambivalence about the experience is almost poignant: "I'm pleased with the picture; I think it's a nice picture. I'm not terribly proud of the use that was made of it. But what are you going to do? You just take the pictures."

The question of photography's influence on actual events is a preoccupation that runs like an anxious pulse through most of the films in the program. Over the years Magnum has included more than 80 member photographers who all seem at one time or another to have brooded about the function of their work. Can pictures make a difference? Can they present a stable interpretation of events? Or, as Meiselas puts it in Pictures from a Revolution: "It's true that photographs stop time, but for people time doesn't stop. Maybe photographs tell a kind of truth about the moments they fix, but is it enough of a truth? And for people who must live in time, is that truth of any consequence?"

Such inklings about the limits of photography might explain the sabbaticals Magnum photographers have spent behind the motion picture camera. Films allow them to interrogate and fix the ambiguities of still images. The clarity and curiosity of the docs now showing at Lincoln Center suggests we should be grateful for those stolen moments.