Interstellar was not merely shot; it was engineered for the largest screens imaginable. Cinematographer Hoyte van Hoytema captured roughly an hour of the film using 15-perforation 70mm IMAX cameras—the highest resolution analog camera format in existence. The remainder of the film was shot on standard 35mm film.
YouTube has emerged as a major free streaming destination, frequently rotating a selection of high-quality, ad-supported movies. For a time, Interstellar was included in this offering, available for free with ads. This availability changes regularly, but it's worth checking the platform's free movie section. Interstellar Free 4k