OnePlus
Switch Between Front and Main Camera auf OnePlus
On a OnePlus phone, switching between the front and main camera does not rely on a hidden gesture. It is a single tap inside the Camera app, though many people miss the icon because it sits in a corner of the viewfinder and looks small compared to the shutter button.
Open Open the Camera app and look at the viewfinder. Then tap on Tap on the camera-switch icon to flip instantly between the rear main camera and the front selfie camera. The same tap works while a photo or video mode is selected, so you do not need to leave the app or change modes first.
In dim environments, switching to the front camera can make the display suddenly turn bright white. This is expected behavior: OxygenOS uses the screen itself as a makeshift flash to add light to your face, since most front cameras do not have a dedicated flash unit. It switches back to normal brightness as soon as you leave the front camera or take the shot.
If the camera-switch icon does not respond, a background glitch in the Camera app is more likely than a hardware problem. Closing the app fully and reopening it usually resolves this before you need to check anything else in system settings.