The Envelope: From Prop. 8 to Joe Paterno, six contenders for feature documentary

It’s notoriously hard to predict which feature documentaries will end up as the film academy’s final five nominees, but surveying the field, one thing is clear: It’s been an extraordinary year for nonfiction on-screen. Even discounting long shots like “20,000 Days on Earth,” a riveting mixed-media portrait of doom-laden rocker Nick Cave, or “Actress,” which follows Brandy Burre, a onetime star of “The Wire” as she tries to reenter the business after a long hiatus, one could make a solid case for dozens of films. In recent years, voters have favored long-form documentaries with great stories behind the lens as well as in front of it. Here are some of the most compelling.

‘The Case Against 8’

When the lawyers who argued opposite sides of Bush vs. Gore in the contested 2000 presidential election joined forces to challenge California’s Proposition 8, they thought taking on the ban on same-sex marriage was the first salvo in a long battle. But in the five years that filmmakers Ben Cotner and Ryan White followed the case to the U.S. Supreme Court, the terrain shifted drastically. The movie was released in June and ends with the information that same-sex marriage is illegal in 31 states; that number has since fallen by more than a third. “It’s shocking how quickly public opinion has shifted,” White says. After a screening in the filmmaker’s hometown of Atlanta, a “very conservative” friend of White’s family came up to him in tears. “I’m sorry,” she said. “I should have come to this conclusion a lot sooner.”

‘Finding Vivian Maier’

When John Maloof bought a batch of Vivian Maier’s photographs at a 2007 auction, he was looking for historical artifacts, not the work of an undiscovered artist. But Maier, who worked as a nanny for much of her life, turns out to have been one of her era’s great street photographers, with a story that unfolds like a thrilling and occasionally troubling mystery. “It’s just miraculous that her work was found,” says Maloof’s co-director, Charlie Siskel. “It does make you wonder how many artists don’t have their work discovered, who labor in anonymity and aren’t lucky enough to have someone find their work and champion it in this way.”

‘Rich Hill’

When Tracy Droz Tragos visited Rich Hill, Mo., as a child, it was a vibrant community with a corner pharmacy and its own newspaper. Now, she says, it’s more like a ghost town. “Rich Hill,” which she co-directed with cousin Andrew Droz Palermo, focuses on three teenage boys trying to make their way in an economically barren landscape, but in classic vérité style, the extent to which it’s about more than their individual stories sneaks up on you slowly, coalescing into a profound and profoundly moving statement about American poverty. “It doesn’t really jump off the page” like more hook-driven docs, Tragos says, “but we hope it’s the kind of thing that one can savor and stays with you.”

‘Tales of the Grim Sleeper’

Lonnie David Franklin Jr.’s arrest in 2010 brought a presumed end to the story of the “Grim Sleeper,” a serial killer who preyed on Los Angeles women for decades. But according to Nick Broomfield’s chilling movie, the true story of Franklin’s suspected crimes has only begun to be told. Prowling the streets of South Los Angeles, Broomfield amasses information that indicates Franklin may have killed hundreds, which, if he’s found guilty, would make him one of the most prolific murderers in history, and that the LAPD turned a blind eye to the killings for years because the victims were poor and nonwhite. The British-born Bloomfield, who now lives part time in Santa Monica’s Ocean Park neighborhood, says the failure to investigate the killings reveals a kind of “modern-day apartheid.” Los Angeles, he says, “is a city that’s always reminded me of Johannesburg.”

‘The Overnighters’

As much as any of the year’s more ponderous best picture contenders, Jesse Moss’ documentary speaks to the mythic core of America. In a small North Dakota city, a pastor fights to find a place for the itinerant workers who have come seeking their fortune and who find a community for whom the American dream comes with a fence to keep outsiders out. “It was ‘Come to Williston, find a bag of money,’” Moss says. “It was like ‘Deadwood.’” With a last-minute reveal that makes it instantly rewatchable, “The Overnighters” tells an intimate story that also engages the largest of questions about national identity and the meaning of faith.

‘Happy Valley’

For college football fans, Penn State football coach Joe Paterno was more than a man, but his legendary status was forever tarnished when it was revealed that he had largely turned a blind eye to allegations that longtime assistant coach Jerry Sandusky had sexually abused youngsters. The target of Amir Bar-Lev’s investigation is less Paterno or Sandusky — although Paterno’s widow and Sandusky’s adopted son and one of the abuse victims do appear in the film — than the football-first culture that allowed them to act, or not act, with impunity. “It’s partially about the people themselves,” Bar-Lev says, “and partially about who we as a culture need them to be.” When so many movies make myths, “Happy Valley” witnesses the end of one and the yawning vacuum left in its wake.