The first Pro Max with camera hardware the smaller Pro did not get: a 47% larger sensor and sensor-shift stabilization.
Released November 13, 2020 · Discontinued September 14, 2021 · From $1,099 (128 GB, unlocked)

The 12 Pro Max is where Apple stopped sharing camera hardware across the Pro line. It got a physically larger main sensor, 47 percent bigger than the 12 Pro's, and sensor-shift stabilization moved from Apple's cinema ambitions into a shipping phone, holding the sensor itself steady rather than the lens. In low light the gap showed. The telephoto went to 65mm for 2.5x rather than 2x, the screen to 6.7 inches at 2778x1284, and the battery to 3687 mAh. At 228 grams it was heavy. Reviewers said so and then said the camera was the best on any phone, which it was for about a year. This is the model that started the pattern of the biggest Pro getting hardware the smaller one does not, and Apple has done it most years since.
Reviewers treated the Pro Max as the camera flagship of the 12 line, with its larger sensor the reason to accept the size.