“Oppenheimer” has already proven a box office success, soaring past $400 million after just its second weekend in theaters. For a film that features a hell of a lot of men talking sternly in offices, that’s pretty impressive. What makes those seemingly drab scenes interesting, however, is not just the gravity of the conversations being had, but the way in which Christopher Nolan and Hoyte van Hoytema treat them as cinematic moments as worthy of large-scale presentation as the Trinity Test itself.

Unfortunately, Imax Cameras aren’t the most practical things. In order to shoot on 70mm film, the cameras have giant mags attached, which makes it quite difficult to maneuver them in the often cramped environs of Nolan’s “Oppenheimer.” The security clearance hearings, for example, which were shot in a real office rather than on a soundstage, required star Cillian Murphy, the various arbitrators, and multiple witnesses to cram into a small room along with the IMAX cameras — something which Murphy claimed to found “very emotional and heavy, but in a brilliant way.”

What you might not think of in these instances, however, is how difficult it was for the sound tech to do his job. As it turns out, those giant IMAX cameras aren’t the quietest. As Vulture reports, Benny Safdie, who plays Hungarian physicist Edward Teller, “thought something had gone wrong” the first time he heard one of the cameras being fired up. As Hoytema explained to the outlet, “It’s a machine that can pull 24 medium-format photography frames per second through a big gauge. And if you have a camera that sounds like a little diesel engine, it’s very hard to create some sort of very tender, sensitive, quiet, intimate moment.”