How do I stop my phone camera refocusing and changing brightness?

A phone camera re-evaluates focus and exposure continuously, which is right when you are pointing at a changing scene and wrong when you have already decided what the photo is of. One long press stops it guessing.

Step by step

1. Tap first to choose the point.A single tap sets focus and metering to that spot for the next moment or two, then the camera drifts back to deciding for itself.
2. Press and hold to lock it.Holding on the same spot until a lock indicator appears fixes both focus and exposure until you tap elsewhere. This is the control that matters and most people never find it.
3. Set the brightness by sliding.With the point set, slide up or down anywhere on the screen. You are applying exposure compensation, overriding the meter. Judge it on the preview — phone previews are honest about brightness in a way viewfinders once were not.
4. Lock before you recompose.Meter and focus on the face, lock, then move the phone to frame the shot properly. Without the lock, moving the phone hands the decision straight back to the camera.
5. Use it for video especially.The visible pulsing in phone video — the picture breathing brighter and darker as someone walks past a window — is auto exposure hunting. Lock before you press record and it stops dead.
6. Protect the highlights when the scene is bright.Lock on the brightest thing you care about and slide down a little. Blown-out white cannot be recovered afterwards; a slightly dark file usually can.
7. Remember to unlock.The lock survives between shots on most phones. A run of unexplainably dark or out-of-focus photos is nearly always a lock left on from the previous scene.
8. Know when to leave it automatic.Fast-changing scenes, children, anything where the subject distance keeps shifting. Locking focus on a moving subject guarantees a miss.

Tips

• Locking exposure across a set of photos of the same scene means they match afterwards, which matters if you are photographing a room or a set of items to sell.
• If the phone will not lock, check you are holding still enough — the gesture needs a moment without movement on most phones.
• The slider is exposure compensation, not brightness added afterwards. Using it changes the actual capture, so it is always better than brightening in editing.

Common mistakes

• Tapping and then immediately moving the phone — A tap is temporary on most phones. The moment the framing changes, the camera re-meters and the careful choice is gone. Hold for the lock instead.
• Leaving auto exposure on for video — Every change of framing shifts the brightness of the whole clip, and it is very obvious on playback and impossible to fix cleanly afterwards.

Questions people ask