OnePlus
Turn Camera Flash On, Off or Auto auf OnePlus
The flash icon inside the OnePlus Camera app controls three independent states: permanently on, permanently off, and an automatic mode that reacts to the light level measured by the sensor right before the shutter fires. If your photos come out too dark, too washed out, or the flash triggers when you did not want it, the mode is usually set wrong rather than the hardware being faulty.
To change it, open Camera app ➔ tap the Flash icon ➔ choose Off, Auto or On. The choice applies to the next shot immediately and stays selected even after you close and reopen the app.
Auto mode measures ambient light in the split second before capture, so it can misjudge backlit scenes or rooms with mixed lighting and skip the flash when you expected it to fire. During video recording, the same toggle switches the flash into a continuous torch instead of a single burst, which drains the battery noticeably faster than photo flash.
Some modes, such as Night mode, Panorama, or certain wide-angle setups, disable the flash toggle entirely because the sensor relies on longer exposure instead of extra light. If the icon looks greyed out, that is the reason, not a system fault.