"The Odyssey" is the first ever movie to be filmed entirely using IMAX cameras (it's also on 65mm film). The main reason being that IMAX cameras are very loud and couldn't be used for quieter, dialogue only scenes. To remedy this, Nolan asked IMAX to come up with a way to reduce the noise, so, IMAX created a custom acoustic containment system called a "Blimp". This box reduced the noise by up to 50%, but, at 300-400 pounds, it sometimes prevented actors from seeing each other. So, they added mirrors to the rig which allowed the actors to look directly into their scene partner's face, while their eyeline still appeared perfectly natural on film. Nolan has been working on this idea for decades and it was a lifelong dream of his that will reshape future IMAX films. It's called the Keighley IMAX Camera.