Exposure Lock (AE-L)
Exposure lock, marked AE-L on most cameras, is a button that freezes the current metering reading. In automatic and semi-automatic modes the camera re-meters every time the frame changes, so a bright sky or a dark wall shifts the settings. Pressing AE-L holds the aperture, shutter speed, and ISO the meter chose. The photographer can then recompose or shoot a sequence, and the exposure stays put until the button is released.
One of Andrea's exposure experiments with the AE-Lock button on a Nikon Z5 II. The reading holds the bright sky, so the clouds keep their shape while the viaduct and hills fall into silhouette.
How exposure lock affects photography
A camera meter reads whatever fills the frame, not what the photographer cares about. A person in front of a window is the classic case. Framed tightly, the face meters well. Step back to include the window and the meter sees mostly glass, darkens the scene, and the face turns to shadow. Exposure lock separates the two steps: meter on the face, lock, then compose the wider frame. The window may blow out, but the subject is correct.
The lock pairs naturally with spot metering. The spot reads a small area, usually the center, so the photographer points it at the part of the scene the exposure should serve: a backlit face, a patch of grass standing in for middle gray, or the sky behind a silhouette. One press locks that value, and the subject can move off center. Exposure compensation still works on top of the lock on most cameras, so a locked snow scene can be pushed a stop brighter.
Exposure lock matters in aperture priority, shutter priority, and program modes, where the camera can change a setting. In manual mode the settings never move on their own, so AE-L does nothing unless auto ISO is active; then it freezes the ISO. A panorama or a burst of frames also benefits. Locking before the first exposure keeps every frame at the same brightness, so stitched images show no steps and sequences do not flicker. On many bodies the same button also locks focus, labeled AE-L/AF-L, and photographers who use back-button focus often remap it or assign exposure lock to a second button.
Tips for using exposure lock
Check the custom menu for the lock behavior. Hold lasts only while the button is pressed. Toggle locks on one press and releases on the next.
Set AE-L to lock exposure only, not focus, so it does not fight with autofocus while recomposing.
Combine it with spot metering. Center the spot on the face, press AE-L, then move the subject to one side of the frame.
For a silhouette, meter the brightest part of the sky, lock, and recompose with the subject in front of it.
Before a panorama, meter the middle of the scene, lock, and keep the lock active through every frame.
Most cameras show an AE-L or asterisk symbol in the viewfinder while the lock is active.
Frequently Asked Questions
Exposure lock is a camera function, usually on a button marked AE-L, that freezes the exposure the meter has chosen. In automatic and semi-automatic modes the camera normally re-meters each time the framing changes. With the lock held, the aperture, shutter speed, and ISO stay fixed, so the photographer can recompose or shoot several frames at the same brightness.
AE-L stands for auto exposure lock. The AE part refers to the camera's automatic exposure system, which reads the scene and picks settings. The L means those settings are locked. Many cameras combine it with autofocus lock on one button labeled AE-L/AF-L, and the custom menu decides whether the button locks exposure, focus, or both.
Use it whenever the subject sits off center and the background is much brighter or darker than the subject. Backlit portraits, a person in front of a window, a silhouette against the sky, and stage lighting are common cases. It also helps for panoramas and sequences where every frame needs the same exposure, since the meter would otherwise adjust frame by frame.
Spot metering reads a small area, usually the center of the frame. Aim the center at the part of the scene the exposure should favor, such as a face or a midtone, and press the AE-L button to hold that reading. Then move the camera to the final composition and take the picture. The exposure stays correct for the spot even though the subject is no longer in the center.
In full manual mode the photographer sets aperture, shutter speed, and ISO by hand, and the camera never changes them, so there is nothing to lock. The one exception is auto ISO. When auto ISO is on in manual mode, the camera adjusts ISO to suit the scene, and pressing AE-L freezes that ISO value until the button is released.
Exposure lock freezes the meter's current reading so framing changes do not alter it. Exposure compensation tells the meter to aim brighter or darker than normal by a set number of stops. They solve different problems and can be used together. A photographer can lock a reading off a snow field, then add plus one stop of compensation so the snow renders white instead of gray.
On many cameras, yes. The default setting often locks both focus and exposure while the shutter button is held halfway, which is why focusing on a subject and recomposing sometimes also fixes the exposure. Other cameras keep metering during the half-press and lock only at the moment of capture. The custom menu usually has an option to choose which behavior applies.
The meter measures the light in the whole frame, or in a chosen zone, at the moment of the reading. Moving the camera changes what the meter sees. Including more sky, a bright window, or a dark wall shifts the average and the camera picks new settings. Exposure lock stops this by holding the reading taken from the first framing.
Hold releases the lock as soon as the finger leaves the button, which suits quick one-off shots and keeps the camera from staying locked by accident. Toggle keeps the lock active until the button is pressed again, which is easier for panoramas, several frames of the same scene, or when the same hand needs to work a dial. Either works; the choice is about habit.
Yes. Mirrorless cameras preview the exposure in the viewfinder, which makes it easier to see when the brightness is right, but the meter still re-reads every time the frame moves. Locking keeps the preview and the final file at the chosen brightness while recomposing. The live histogram and highlight warning make it simple to confirm the locked value before pressing the shutter.
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