Whenever you use some form of automatic exposure, there’s the possibility to lock the exposure, but after a few seconds that locked exposure is gone, until you use AE-Lock with hold.

Auto exposure lock / AE-lock

It doesn’t matter if you’re a new photographer or a seasoned professional, if your camera is set to anything except full manual, then you need to know about exposure lock. Also be aware that manual with auto ISO doesn’t count as full manual either.

Conventionally with one-shot AF you aim the camera at your chosen subject and press the shutter which causes it to focus and when focus completes the camera beeps to tell you it has locked focus. If your camera is set to the default evaluative metering it will also automatically lock exposure for you.

However if you use spot, partial or centre weighted metering there is no automatic exposure lock. Also if your camera is set to servo AF there is also no automatic exposure lock. There are many situations where you may want to meter the scene and lock the exposure and so cameras have an AE-lock button, often called the “star button” since it has an asterisk / star icon on it. When you press the star button the camera locks the autoexposure and displays a star icon on the screen or in the viewfinder. Each camera has a preset time before the metering resets and the lock is cancelled, typically 8 seconds. Though if you keep half-pressure on the shutter then the exposure stays locked until you release it.


You can change the default 8s metering timer, usually from 4s up to 30 minutes depending on the camera, but additionally the lock can stay locked until you unlock it, or the camera switches off – this is ae-lock with hold.

On  the screen above you can see that the exposure has been locked, some cameras also add an H character to show its exposure lock with hold. To release the locked exposure simply press the star button again or switch the camera off.

When to use AE-lock with hold

One of the times I regularly use AE-lock with hold is when shooting motorsports, especially if it racing on a track or circuit. Here you can measure the exposure – using the track as a good reference – before pressing the AE-lock with hold button. Now it won’t matter if the first racer is in a white car, black car, yellow car, or mirrored silver car, the exposure will be the same since the light illuminating the cars is still the same.

I have also used AE-lock with hold when photographing birds in flight. I can preset the exposure and apply the lock before the bird is in the frame. Though you have to take care that you don’t move too far so that the light on the subject changes.

Configuring AE-lock with hold

Use your camera’s custom controls or custom buttons to switch the assigned function of the star button to AE-lock with hold.

Back button focus users…

When you configure back button AF, you make a choice as to the function of the half-press of the shutter, it is either metering start or metering lock. Which means that your specific configuration back button AF setup may override the usefulness of AE-lock with hold, depending on how you operate the shutter. Either way you can also use the star button for AE-lock with hold on many cameras.

Advent Calendar of Tips

This year I’m writing a quick tip each day up until the 25th of December, here’s some of the others I have already posted.


About the author

Full-time photo tutor and photographer. I love to share my knowledge and skills to make photos, videos and teach others. I write books and articles for photo magazines and I always have at least one Speedlite flash in my camera bag