From the late 1940s on he worked for Cruzeiro magazine, similar to Life or Look, first as a reporter and then also as a photographer. He met Lucy, then a music student, while on an assignment, and they married in 1954.

Crucially, Mr. Barreto covered movie stories and got to know directors like Nelson Pereira dos Santos, Glauber Rocha and Carlos Diegues, associated with what by the early 1960s was evolving into the Cinema Novo movement. That eventually led to an invitation to write the screenplay of “Assault on the Pay Train,” a commercial success in 1962 and one of the first films of the gritty, socially engaged Cinema Novo to win attention and awards at international festivals.

“From the beginning the Cinema Novo was a movement that was as much political and ideological as cinematic,” Mr. Barreto, his bushy eyebrows rising and falling, said during an interview this month at the family’s New York apartment on the Upper West Side. “When ‘Assault on the Pay Train,’ which had all those elements, exploded at the box office, that gave us credibility.”

He was then enlisted as the cinematographer on Mr. Pereira dos Santos’s “Barren Lives” and as cinematographer and producer of Mr. Rocha’s “Earth Entranced,” both of which won prizes at the Cannes Film Festival. True to the Cinema Novo’s motto that all that is necessary to make a film is “an idea in the head and a camera in the hand,” both of those influential works, as well as many others that went on to great success in Brazil and abroad, were edited in the small guest house behind the Barretos’ home in Rio.