The most fundamental change is that it has a completely different, much larger primary sensor. It’s 47 percent bigger and uses 1.7-micron pixels, the largest Apple has ever used on an iPhone. While the sensor is still 12 megapixels in resolution, the larger pixels and surface area mean it’ll capture much more light and should turn out cleaner results. Together with the new f/1.6 lens, Apple is claiming an 87-percent improvement in low-light performance over the 11 Pro Max. That’s huge.
The 12 Pro Max also uses a different type of image stabilization technology called sensor shift, which moves the sensor around multiple axes in response to external motion. It’s commonly found in DSLRs and mirrorless cameras, whose makers then benefit from not having to build OIS into lenses. Apple says this adds a full stop of stabilization — in other words, letting you use twice as long a shutter speed, all things being equal. That takes the 12 Pro Max up to two-second handheld exposures in regular shooting, which could reduce the need for night mode in all but the darkest conditions.
Finally, the 12 Pro Max has a longer (and slightly slower) telephoto lens than the 12 Pro, at 65mm-equivalent f/2.2 versus 52mm-equivalent f/2.0. Apple says that this “allows for longer framing in the classic portrait style,” and while 65mm isn’t a common portrait photo length at all, it’s true that it’s more conventionally appropriate than 52mm. It also expands the 12 Pro Max’s optical “zoom” reach from 2x to 2.5x; Apple markets this as a 5x zoom range, but that’s including the 13mm-equivalent ultrawide lens. (Phone makers that tout their 5x periscope zoom lenses are counting from the regular wide lens;
the Huawei P40 Pro’s 5x lens is 125mm-equivalent, for example, meaning the total zoom range of the phone is more like 7x.)