SOMETIMES YOU have to just pick up the camera, point it and shoot. Abraham Zapruder will tell you that. Worry about the ethical questions later.

Samira Makhmalbaf, the 17-year-old daughter of renowned Iranian director Mohsen Makhmalbaf, was clearly presented with such an opportunity.

In Iran, an impoverished villager and his blind wife had just made headlines after revelations that they had imprisoned their twin teenage daughters since birth. The government was alerted when the residents of this Tehran suburb wrote a letter of appeal. It told of Ghorbanali Naderi, a 65-year-old unemployed villager, and his Turkish wife, Soghra Behrozi, who had been holding Massoumeh and Zahra, 12, behind lock and key for their whole lives.

Two children imprisoned in their own homes for 12 years? A father and a blind mother who never educated or even cleaned them? Makhmalbaf had always wanted to be a director like her father, who is known for such works as "The Peddler" and "The Cyclist." She picked up the camera -- which the Iranian government had issued for her father's next film. She pointed. She shot. But she did a little extra. She wrote a script.

The result is "The Apple," an extraordinary movie about human cruelty and degradation, which was selected for last year's non-competitive "Un Certain Regard" category at the Cannes film festival.

But this movie provokes as many questions as it poses. Instead of filming things as they were, Makhmalbaf turned her film into a reenactment exercise. She talked the subjects into playing themselves. Is Makhmalbaf's movie a mission of moral outrage and compassion, or just artistic opportunism?

When the cameras started rolling, it was four days after the news had come to light. Naderi was furious at erroneous stories that he had chained his daughters. The fact that he deprived them of light, life and human warmth apparently was beside the point.

Getting his permission to make the film was "a very simple process," according to Makhmalbaf, who told the father he'd be able to speak his mind. Naderi even consented to participate -- along with his daughters -- in a dramatic retelling of the story, as orchestrated by Makhmalbaf and her father.

"The Apple" isn't a documentary so much as surrealistic burlesque. Naderi, whose heedlessness to his moral crime is remarkable, plays a central role in his own damnation. And the two girls -- who didn't have the faintest idea about how to live in this world -- become his unwitting costars.

Between the lines of Makhmalbaf's strange agenda, the emotional facts come out loud and clear. Naderi repeatedly condemns himself without realizing it, howling on about his humiliation, and acknowledging -- little by little -- that he didn't do right by his children.

The mother -- a menacing presence -- hangs in the dark background, refusing to come forward, hidden in a shawl when she does.

We learn these girls were never bathed. They were padlocked indoors because the mother couldn't deal with them, because the father feared they might be raped -- the reasons Naderi gives are endless and ludicrous.

They had no interaction with people, no schooling, no nothing. Now in the real world, they are learning that life is bigger than the darkness of their room. Will the extent of their enslavement ever hit them? Will they ever achieve their human potential? These questions hang over the film unanswered.

Instead, we follow the "story," as the girls -- treated at the Welfare Department before returning to their parents -- come home and learn of life. They bang with spoons on the cell door that barricaded them inside. They cower from their father. They befriend local girls who teach them hopscotch.

To demonstrate their inability to understand real life, director Makhmalbaf has them approach an ice cream seller, unaware that they have to pay money for the transaction. The girls, flummoxed by the boy's demands that they produce money, steal the ice cream.

Additionally, Makhmalbaf shot many of the scenes from several angles, allowing herself the freedom to cut from one face to the other. This means she made the "performers" redo their "lines" frequently for the benefit of the camera.

In light of the parental exploitation we're supposed to be wringing our hands over, the irony is hard to ignore. Naderi and his wife can rightfully expect further condemnation; the Makhmalbafs can anticipate festival prizes. But whatever the ethical questions, the movie gets through to us anyway. There is nothing more haunting than the faces of those two girls, two angels who were kept in hell for more than a decade and have emerged, blinking into the light.

THE APPLE (Unrated, 85 minutes) -- Contains disturbing material. In Farsi with subtitles. At the Cineplex Odeon Inner Circle 3.

CAPTION: Twin sisters Zahra Naderi and Massoumeh Naderi were imprisoned by their parents for 12 years.