WHEN they don’t involve sailors kissing nurses, the symbolic photographs of New York City usually involve skyscrapers: Alfred Stieglitz’s snowy shot of the Flatiron Building; Berenice Abbott’s electric “Night View”; Margaret Bourke-White perched atop an art-deco eagle of the Chrysler Building. And Lewis Hine’s celebrated portrait of 11 Depression-era ironworkers, lunching along an I-beam on the unfinished Empire State Building.

No?

No, on several counts.

The shot isn’t by Hine. And it’s not atop the Empire State Building — despite common misperceptions, misrepresentations and an Internet that insists otherwise. Taken Sept. 20, 1932, during the construction of Rockefeller Center, the well-known portrait of 11 immigrant laborers, legs dangling 850 feet above Midtown, ran in the Oct. 2 Sunday supplement of The New York Herald-Tribune, with the caption “Lunch Atop a Skyscraper.” Everybody knows the picture. Nobody knows who took it. And for most of its 80 years no one has known who’s in it.

A bit of the mystery is resolved in “Men at Lunch,” a documentary about the photo that’s featured in the current DOC NYC series at the IFC Center in Greenwich Village. Its director isn’t making any exorbitant claims. “We just muddied the waters a bit,” Sean O Cualain said with a smile during a recent interview in New York. “It was already a complex story full of unknowns. And we added a few more unknowns.”...