EV lock hold reading
Lock the meter so the next reading does not overwrite this one.
Where to find it
Viewfinder Hold Reading button (bottom area, after a reading is active)
Summary
Tap the lock button to pin the current exposure reading. New measurements will not overwrite it until you unlock. Lets you meter once for the key tone, then recompose, change focal length, or move the camera without losing the reading.
Detail
How it works
What it does
Take a reading on the key tone (the face, the sky, the brightest highlight you care about). Tap the lock button. The exposureLocked flag flips on; from that point on, taps on the preview, motion-triggered re-measurements, and gated stabilization readings all skip until you unlock.
Typical workflow
Point at the subject, take the reading, lock. Then recompose to your actual frame (the subject does not have to be in the centre, the meter does not have to see them anymore). Take the photograph with the locked exposure values. Unlock when you move to the next scene.
How to unlock
Tap the lock button again. The button visually confirms its state (active/highlighted when locked). Switching metering modes or starting a multi-spot session also clears the lock so you do not get surprised on the next reading.
Multi-spot interaction
In Multi-Spot mode the lock works slightly differently: locking after the first spot pins the running average, and subsequent taps add new spots without overwriting the locked composite. Useful for incremental zone-system planning without losing the headline reading.
Pairs with stabilization gating
Stabilization gating (2.15) prevents new readings while you wobble. The lock sits one layer above: even when the phone is steady and gating would allow a new measurement, the lock still blocks the overwrite. The two together make handheld zone work practical.