What Is AF-Lock? (Also FE, AF, AE Lock)

A guide to these DLSR camera settings

The FE-, AF-, and AE-Lock buttons on your DSLR camera give you greater control over how your photos turn out. AE-Lock locks in the current exposure settings while the AF-Lock locks the focus. FE-Lock is used exclusively for locking flash exposure settings.

Information in this article applies broadly to different types of DSLR cameras. Consult your device's manual or the manufacturer's website for further guidance.

What Is AE-Lock? 

AE stands for automatic exposure. The AE-Lock button allows users to lock their exposure settings, such as the aperture and shutter speed, to ensure consistency when taking photos. That way, you don't have to constantly readjust everything each time you press the shutter button in difficult lighting situations.

Use AE-Lock when taking panoramic pictures to ensure that the lighting for each individual photo looks the same when you stitch them together.

The AF and AE Lock buttons on the back of a Nikon DSLR.
Nikon

What Is FE-Lock? 

FE stands for flash exposure. FE-Lock is especially useful when photographing reflective surfaces, which can confuse flash metering, or when the subject lacks a definite a focus point. With some cameras, the FE-Lock only lasts for about 15 seconds, or for as long as you keep the shutter button half-pressed.

Many DSLR cameras don't have a dedicated FE-lock button. Instead, the FE-Lock feature is tied together with the AE-Lock. Some expensive DSLRs have a separate FE-Lock button, and others allow you to assign FE-Lock to a custom function button. 

What Is AF-Lock? 

AF stands for autofocus. All DSLRs have an auto-focus feature that activates when you snap a photo, but if you hold down the AF-Lock button, you can maintain the same focus point even if you adjust the composition of the scene.

Not all cameras have an AF-Lock button, but you can still lock the autofocus by pressing the shutter button halfway. By keeping your finger on the shutter button as it's pressed halfway, the focus remains locked. Sometimes, the AE-Lock and AF-Lock share the same button, allowing you to activate both at the same time.

AF-Lock can be very useful if you want to focus on a subject that is on one side of an image. That way, you can lock the focus on the subject, and then recompose the image without taking your finger off the shutter button.