In photographic wanderings around New York City, Paul Strand sometimes used a fake lens so his subjects wouldn’t know their pictures were being taken.

Partly by this means, he brought greater spontaneity and realism into the photographer’s worldview circa World War I, leading an art form that had recently imitated painting into the modern age on its own terms.

Until his death in 1976, Strand, whom the Philadelphia Museum of Art regards as “one of the greatest photographers in the history of the medium,” produced work infused with left-of-center social views and curiosity about people and localities all over the globe.