Here's how to use the camera zoom functions on the iPHone 15 Pro Max (also partly applies to similar models)...
Open the Camera app. Tap on ".5", "1x", "2", or "5" icon to choose that focal length. Tap the circled "1x" icon to switch to the 28mm focal length (1.2x optical zoom). Tap the circled "1x" icon again to switch to the 35mm focal length (1.5x optical zoom). Tap again to return to the default 1x focal length. Long press on any of the icons to show a zoom control. Drag on the screen to change zoom. Note: Extreme zoom uses digital zoom, which involves some compromise in image quality.
To Disable the Extra Focal Lengths
If you don't need the extra focal lengths, you can disable them like this... Open the Settings app. Scroll down and tap Camera. Tap Main Camera. Under Additional Lenses, toggle off the switches next to 28mm and/or 35mm.
Change Default Focal Length
To change the default focal length setting... Open the Settings app. Scroll down and tap Camera. Tap Main Camera. Under Default Lens, select: "Default to 24mm - 1x", "Default to 28mm - 1.2", or "Default to 35mm - 1.5x".
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