The iPhone 15 Pro Max features a new Telephoto lens that uses a tetraprism design to enable 5x optical zoom, an improvement over the 3x zoom that's available in the iPhone 15 Pro and the prior-generation iPhone 14 Pro and Pro Max models.
5x optical zoom allows for 25x digital zoom, and while that's the most zoom an Apple device has offered, it still falls below the competition.
Samsung's latest Galaxy S23 Ultra smartphone has 100x Space Zoom that can capture images from 330 feet away. The Pixel 7 Pro has 30x digital "Super Res Zoom" with its 5x optical zoom lens. Apple has never leaned into digital zoom because the quality is poor. Optical zoom provides a crisp, clear image using the camera hardware, but digital zoom uses software enhancement to crop in.
5x optical zoom is an iPhone 15 Pro Max-specific feature that is not available on the iPhone 15 Pro. Both devices share other camera improvements, though. The 48-megapixel main camera has a larger sensor that lets in more light, and it can be set to 24mm, 28mm, and 35mm focal lengths.
There's also an updated 13mm Ultra Wide camera, and second-generation sensor-shift optical image stabilization.