Many tears were shed at the world premiere screening of “127 Hours” at the Telluride Film Festival on Saturday afternoon. But few in the audience of some 500 cried harder than Aron Ralston, the hiker who famously cut off his right forearm and is the subject of director Danny Boyle’s new movie.

Boyle has described the film, which Fox Searchlight is releasing on Nov. 5, as an action movie in which the hero doesn’t move -- a reference to how Ralston (played in the film by James Franco) was pinned by a falling boulder in an isolated canyon and was forced to amputate one of his limbs in order to survive.

But as Boyle has proved throughout his filmmaking career -- his last film, “Slumdog Millionaire,” which premiered at Telluride two years ago, not only won the Oscar for best picture but also for directing, cinematography and editing -- he can take a scene that at first glance looks unfeasible to film and make it both visually kinetic and emotionally moving. Christian Colson, who produced “Slumdog Millionaire” and “127 Hours,” said Ralston’s tale “was a story that on paper felt impossible to tell as a movie.”

Boyle appears to have taken that as a challenge.

In “127 Hours,” Boyle’s cameras (he used two cinematographers, Anthony Dod Mantle and Enrique Chediak) never stop moving. They soar over the desolate Utah canyons where Ralston was stuck for all those hours. They swim through the water bottle as he drinks his last drink. They penetrate his arm, as Ralston’s knife stops when it hits bone. They enter a duffel bag that Ralston has put over his head to stay warm in the 44-degree chill, the bag’s nylon shell becoming a miniature movie screen in which Ralston briefly revisits the world he has left behind and might never see again.

Most directors would have cut away from Ralston to focus on the building rescue effort, but Boyle doesn’t. Franco is in virtually every second of the movie. As he becomes increasingly dehydrated, he starts to hallucinate, and it is after one such hallucination -- in which Ralston thinks he might be seeing a son who is not yet born -- that Ralston decides to take dramatic action and cut himself out.

In making the movie, Boyle knew that if the audience averted its eyes when Ralston ultimately broke the bones in his arm and severed a tangled mass of tendons, muscle and nerves with a dull knife, “127 Hours” would have failed. Although one member of the Telluride audience apparently passed out during the graphic sequence, very few looked away. Ralston, who was attending the screening with his wife, was visibly moved throughout the film, but the tears really started flowing when he watched the reenactment of his primitive surgical procedure. The relief in the theater was palpable -- if there’s such a thing as quiet cheering, there it was.

“It’s like we all just went through what I did,” Ralston told the audience after the screening’s conclusion. Even though “127 Hours” takes some dramatic liberties (a flash-flood scene, in particular), the movie was “all very accurate and real,” Ralston said.

“This is insane,” are the first words Ralston speaks as soon as he is trapped by the large falling rock. His situation was doubtless that. Yet even crazier is that Boyle has made Ralston’s tale spellbinding — truly an action movie in which the hero doesn’t move.

-- John Horn in Telluride, Colo.

Photo: James Franco as Aron Ralston in "127 Hours." Credit: Chuck Zlotnick / Fox Searchlight