One of the best tidbits of wisdom imparted to young directors is to “make the movie you ARE making, not the movie you PLANNED on making.”

Such is the case with British photojournalist Zana Briski, who spent years living in the red-light district of Calcutta to study the harsh conditions of impoverished prostitutes. Through time, Briski instead became enamored with the children of these women and decided to recruit some of them for a class in photography. She handed out cameras and assigned the students (ages 10-14) to capture their environment.

Despite its somewhat misleading title, “Born Into Brothels” is the story of how these fledgling shutterbugs create work that receives international attention.

“One has to accept life as being sad and painful,” says Puja, one of eight subjects focused on in the film.

The day-to-day existence of these kids is certainly unpleasant. They share rooms with harlots and their seedy customers. (“The men who enter our building are not so good. They are drunk and come inside and shout and swear,” Puja says.)

Most are physically and verbally abused. One has a father who is near catatonic from smoking so much hashish. Another admits that her dad tried to sell her before her aunt intervened. It’s a given that the only career option once the girls survive puberty is to go “in the line” — a local euphemism for streetwalking.

Yet Briski and co-director Ross Kaufman take this potentially grim setting and turn it into a tale of inspiration.

A child photographs a cab in Calcutta during a scene from the Oscar-winning documentary, Born

What allows this to happen is the fact the kids’ pictures are so striking. The shots unveiled throughout the film display a childlike innocence when observing a hostile world. The images are both stark and colorful, depressing and idealistic.

There is some genuine talent exhibited here, especially from 12-year-old Avijit. When the pudgy boy is whisked away to Amsterdam to attend a convention of young photographers, he deconstructs other people’s work with the confidence of a working art critic.

This collective ability is all the more impressive considering the environment the street urchins are raised in.

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Briski says in narration, “It’s almost impossible to photograph in the red-light district. They’re frightened of the camera. They’re frightened of being found out. Everything is illegal.”

The filmmakers show that the pimps, hookers and drug users who populate their neighborhood aren’t exactly enamored with the kids, perceiving their snooping and snapping as a nuisance. (Maybe they have careers ahead of them as paparazzi.)

As can be expected, Briski and Kaufman bring more of a photographer’s eye to the project rather than a storyteller’s. The movie doesn’t have the assured narrative arc of a documentary such as the superior spelling bee-themed “Spellbound,” which shares a few structural similarities with this film. This leads to a flimsy third act that can’t quite match the momentum of the earlier portions. And some of the cinematic approaches are borderline amateurish, as when a field trip to the ocean is interspersed with a montage of the young passengers dancing, complete with cheesy video grabs.

The pair is content to let the compelling subject steer itself, and for the most part that succeeds. Enough so that the effort earned an Oscar this year in the documentary feature category, besting higher-profile flicks such as “Super Size Me” and “The Story of the Weeping Camel.”

But it’s a testament to the abilities of these Calcutta children that the most touching images revealed in “Born Into Brothels” are those taken by them.