Leonardo DiCaprio, Alejandro Gonzalez Inarritu discuss challenges of filming The Revenant

Filming the harrowing wilderness epic The Revenantwas like "rock climbing without a rope," director Alejandro Gonzalez Inarritu told a robust crowd on Monday at one of the first public screenings of the film.

"There is no way down," Inarritu said. "You have to go up or you die. There was no choice for us."

After the credits rolled and the audience stood up to cheer, Inarritu was joined on the Samuel Goldwyn Theatre stage at the Academy of Motion Picture Arts and Sciences by stars Leonardo DiCaprio, Will Poulter and other members of his filmmaking team, who braved a brutal British Columbia winter to shoot the film this past year. The crew also shot scenes in Alberta.

He put the final touches on the film last week for its Oscars-qualifying limited release on Dec. 25 followed by a nationwide expansion in January.

Set in 1823, The Revenant, based on a 2002 novel by Michael Punke, follows Hugh Glass (DiCaprio) and a team of fur trappers (including Poulter, Tom Hardyand Domhnall Gleeson) on an expedition cut short by a vicious ambush the first scene that they shot.

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Soon after, Hugh is mauled by a bear and left for dead by his fellow frontiersman. He wills himself to survive and endeavours to enact revenge on those who have wronged him.

"This is a very linear, straightforward, brilliantly simplistic screenplay...we wanted to find the poetry in between that," DiCaprio said of his performance, which requires very little dialogue for a 151-minute movie.

Trying filmconditions

"It was about us immersing ourselves in nature and putting ourselves as close as we could to the struggle of these people and finding the thru line in that process."

That immersion wasn't exactly a pleasant experience all of the time. Not only were the conditions trying and "absolutely against [the crew]all the time," but Inarritu was uncompromising in his stylistic ambitions he and cinematographer Emmanuel Lubezki shot everything in natural light and with the painstaking detail of his signature long takes.

It proved to be a very different experience than that of Birdman,which earned Oscars for Inarritu and Lubezki.

"In Birdmanwe were in the cozy corridor of the set. Everything was controlled," said Inarritu.

"The odyssey of making this film became even bigger than what these guys were going through."

'Abeautiful blur'

For the actors, too, shooting The Revenantwas a feat unlike that of any other film, with elaborate rehearsals and preparation months out, only to have minutes to shoot on the day.

"It's all a beautiful blur to me," DiCaprio said, likening executing Inarritu's long shots to performing theatre every day.

"You have to rehearse meticulously and then it's a mad, intense scramble to capture this magic light, this precious hour and a half...It became very much like an un-humorous Saturday Night Livesituation."

The tension of getting the shot right translates into the movie and the performances, DiCaprio said, and was a bonding element between the cast and crew.

"This is the most difficult film, I think, that any of us have ever done."