Samsung
Set the Volume Key Function in Camera auf Samsung
On Samsung phones, the volume keys are set by default to act as a camera shutter once you open the Camera app. Pressing either button fires off a photo or starts a video recording, which is useful for one-handed shots or when the phone is mounted on a tripod.
The downside shows up when the buttons get pressed by accident, for example while pulling the phone out of a pocket or adjusting your grip. Each unintended press triggers a shot or clip you did not mean to take. Samsung's camera settings let you reassign the same buttons to control zoom or the system volume instead, so stray presses stop wasting shots.
To change the behavior: Tap on Camera ➔ Tap on Settings ➔ Tap on Shooting methods ➔ Tap on Press Volume keys to ➔ Choose an option.
Pick Take pictures to keep the shutter shortcut, Zoom if you shoot a lot of video and want quick zoom access, or Volume if you mostly use the on-screen shutter button and want the side keys to behave normally. The setting only affects behavior while the Camera app is open.