GoKawiilThe best possible spectator experience is watching a movie shot on IMAX 70mm film and projected from an IMAX 70mm film print. With its square 1.43:1 format and 69.8 x 48.5mm frame size, IMAX 70mm (also known as IMAX 15/70 due to the 15 sprocket holes per frame) is projected horizontally on colossal 59 x 79-foot screens to fill your field of vision in all directions.
The extra resolution, up to 18K equivalent, means that images are pin sharp, even on that huge screen. The projection is bright as well, thanks to the use of single or even dual 15kW water-cooled xenon bulbs — up to 7.5 times brighter than the ones you'll find in regular theaters. All of that technology makes IMAX 70mm more immersive than any other format.
However, there are only around 24 such theaters in the US, nine in Canada and six elsewhere around the world. The other challenge is that only one feature film has been fully shot on IMAX (The Odyssey, of course). This comes down to cost. The Odyssey production cost was $250 million and required a special new camera system to reduce noise and allow dialog to be filmed. On top of that, each IMAX 70mm projection print reportedly cost around $80,000.
Your next best bet is seeing a film shot using a mix of IMAX 70mm and Super Panavision 70mm film, then projected in an IMAX 70mm theater. That still offers the full IMAX scale, brightness and 1.43:1 projection on those same large screens. However, those films lack the full resolution of true IMAX in some scenes and won't look as sharp. Films in that category are more common but still pretty rare and include Oppenheimer, Tenet, Dune Part 3 and Sinners.
Films shot on digital or 35mm, then upscaled, transferred and projected on IMAX 70mm film are a further step down. That process results in another drop in sharpness, though you retain the immersive 1.43:1 aspect ratio, colossal screen size and awesome brightness. Many recent films fit that bill, including Barbie and Project Hail Mary, both shot on Arri Alexa 65 digital cameras and screened on IMAX 70mm at select theaters.