For all those Nikon digital camera users out there, do you know the difference between the AE-L/AF-L button?
If you don’t, then this article is for you.
If you do know their purpose and how to use them, keep reading. You’ll still learn something new.
What Is AE-L?
AE-L stands for auto exposure lock, while AE-F stands for autofocus lock. The AE-L/AE-F button ‘locks’ the autoexposure and autofocus.
By pressing the AE lock button, you are forcing your camera to use certain setting values. If you are using Program, Aperture Priority, Shutter Priority or scene modes, this will help.
Shutter speed, aperture, ISO and white balance can all be set with this button. Using any automatic modes in camera means that the metering sensor determines the optimal exposure.
Your camera re-evaluates the light every time you recompose the shot. By pressing this button, you ‘lock’ the exposure you are happy with.
This feature is helpful in many different ways. One example of these is the capturing of panorama images. Here, it is very important to use the same exposure from frame to frame.
It is impossible to match frames if the exposures are different. Even if you’re using the best software.
Here’s another good example. Imagine you are photographing a subject with a constantly changing background. Keeping the subject the same is important. By using the AE-L/AF-L button, you keep the light consistent.
This is especially true if you don’t want to switch to full manual mode.
What Is AF-L?
The AF-L button stops the lens from reacquiring focus when you recompose. That means our focus point doesn’t change, even if your composition does.
For example, photographing indoors can be difficult for your autofocus. Even if you’re using the centre focal point, which is the most accurate. It doesn’t mean you want to have the subject in the middle of the frame.
To focus using the centre focal point is the easiest. But, by recomposing the shot means the camera will attempt to refocus the shot.
You can set your camera to “AF-C” or “Continuous Focus Mode”, which will follow the focus of a moving subject. Handy in some cases, but deadly when used wrong.
If you do not want to deal with these situations, you could use the AF-L lock button. You retain focus on your subject, and can recompose however you want.
You need to keep your finger on the button for this to work. You do need to be careful when recomposing shots such as these, to avoid bad focus. This is down to the focus plane.
This focus plane, parallel to the camera sensor, will sometimes change. This results in unattractive focuses. Especially when using large apertures.
The default settings for the AF-L/AE-L button are to lock exposure and focus. Entry-level DSLRs have limited control over this button’s functionality.
Pro-level DSLRs allow you to use custom settings. There are many options to assign AE-L/AF-L button. For example, the Nikon D3400 has five options for this button.
These are AF/AE lock, AE lock only, AF lock only, AE lock (hold) and AF-ON.
Other Nikon DSLRs, like the Nikon D500, have all of these, plus another 12 ways to control this button. The camera model is what allows the customisability of this button.
Same goes for Canon cameras, where higher end products give you more control over the AE-L/AF-L button.
Types of AutoExposure and AutoFocus Lock Modes
AF/AE lock – This is the AE-L/AF-L button’s default behaviour. This locks both the exposure and lens focus. It is only active when holding down the button.
AE lock only – This feature only locks the camera exposure, leaving the focus to refocus when the frame is recomposed. Again, it is only active when the AE-L/AF-L button is held down
AE lock (Reset on release) – The exposure will be locked once you press the AE-L/AF-L button. It will stay locked until you capture an image, even if released.
AE lock (hold) – The exposure is locked even after capturing single or multiple images. The lock will be removed automatically if inactive for a specific time period.
This can be changed in the “Auto meter-off delay” menu setting. It can be removed by pressing the button again.
AF lock only – Only focus will be locked while the AE-L/AF-L button is pressed. It is removed when you release the button.
AF-ON – This allows the AE-L/AF-L button to acquire the focus, instead of pressing the shutter release button. By pressing the shutter release button, you do not refocus, only capture the scene.
This works the same way as ‘back button focusing‘.