iPhone Photography

Photo -> Video

Long press capture button become Video mode. Move to the right to lock.
=> "QuickTake video"

https://support.apple.com/guide/iphone/take-videos-iph61f49e4bb/15.0/ios/15.0

AF Lock

You can change the camera focus and exposure to a specific area. Before you take the photo, tap the place on the screen that you want to adjust. If you want to keep the focus and exposure in the same spot, press and hold on the screen until you see AE/AF Lock.
https://support.apple.com/en-us/HT207260

You can tap and lock the focus on the subject, and then drag up or down to get the exposure right.

Portrait Mode

You can change the aperture on top right.

Panorama

Move in the opposite direction can stop it. Pressing the button resulted in blurry.

Up-side down

Turn your phone up-side down and taking photos can take photos that you dont need to get down so much.