The iPhone 12 Pro Max may have better cameras than the iPhone 12 Pro
The iPhone 12 Pro and iPhone 12 Pro Max will feature different camera sensors, according to DuanRui - who tweets as @duanrui1205. Last year, Apple distinguished its Pro and Pro Max iPhones by screen size, having equipped the iPhone 11 Pro and iPhone 11 Pro Max with identical cameras. Apparently, the iPhone 12 Pro Max will possess enhanced telephoto and ultra-wide-angle cameras, though.
Specifically, the ultra-wide-angle camera sensor in the iPhone 12 Pro Max will have a pixel width of 1.7 μm, which will be 47% larger than the one in the iPhone 12 Pro. Both sensors will have an f/1.6 aperture and Apple's new 7P lens, but the Pro Max will have an 'expansive' ultra-wide-angle camera. Presumably, this means that the Pro Max will have a wider field of view than the 12 Pro.
Additionally, the 12 Pro Max will sport a telephoto camera with a focal length of 65 mm, compared to a 52 mm telephoto camera in the Pro. DuanRui adds that the 12 Pro Max will offer '5x optical zoom' too, while the Pro will support up to '4x optical zoom'. However, the leaker prefaces these claims with that they will be provided by 'the entire system', so their telephoto cameras may not achieve these zoom levels on their own. Instead, 4x and 5x optical zoom may refer to the differences in focal lengths between the ultra-wide and telephoto cameras.
If that is the case, then the 12 Pro Max may have a 3x telephoto lens and the 12 Pro a 2x one. Adding these values to a '2x optical zoom out' ultra-wide-angle camera, as Apple refers to the ultra-wide in the iPhone 11 series, would yield 4x and 5x optical zoom for the 12 Pro and 12 Pro Max.