An untitled work from Bruce Davidson’s 1980-1981 “Subway” series, which was influenced by early street photography.

If you live in a city, you expect a certain amount of your life to be lived on the stage of the street. Six photographers translate that idea into art in the National Gallery of Art’s “I Spy: Photography and the Theater of the Street, 1938-2010,” which features dozens of pictures that capture urbanites going about their business.

The show’s artists — Harry Callahan, Bruce Davidson, Philip-Lorca diCorcia, Walker Evans, Robert Frank and Beat Streuli — each set out to covertly capture scenes of daily life. All six went about it a little differently.

Walker Evans took his Depression-era New York subway portraits by hiding a camera in his coat. In his photos, passengers gussied up in hats and button-downs look weary against a background of 1930s advertisements.

Harry Callahan, a self-taught photographer who believed “the camera could break free to depict the world,” did similar work in Chicago. In 1950, he shot a surprisingly intimate series of photos of women’s faces as he walked down the city’s streets.

The photographers “were laying themselves open to whatever might happen,” says Sarah Greenough, senior curator of the NGA’s photography department.

Later photographers set their own unusual parameters. Robert Frank shot only what he could see from the window of a bus in New York City in 1958; Bruce Davidson chose to photograph only within the Big Apple’s graffiti-covered subway system in the 1980s. Working in 1997, Philip-Lorca diCorcia created an elaborate method for photographing subjects, with a system of synchronized flashes hung on lampposts and street signs. He watched from afar, activating a prefocused telephoto lens whenever someone stepped over a designated mark.

One man, an Orthodox Jew, did not appreciate being included in diCorcia’s ouvre. He sued diCorcia for violating his privacy after he realized he was in the photos. But a judge ultimately ruled that diCorcia was creating art.

That’s the ultimate message of “I Spy” — that the works document the evolution of a society. “A great photograph … speaks to something important to a particular time or place,” Greenough says. “It summarizes the spirit of the time.”

National Gallery of Art, 4th Street and Constitution Avenue NW; to Aug. 5, free; 202-737-4215, (Archives)