The FE, AF, and AE Lock buttons on your DSLR camera give you more control over how your photos turn out. AE Lock locks the current exposure settings, while AF Lock locks the focus. FE Lock is used exclusively for locking flash exposure settings.
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AE stands for automatic exposure. The AE Lock button lets you lock exposure settings, such as aperture and shutter speed, to ensure consistency when shooting. This way, you don’t have to readjust everything every time you press the shutter button in difficult lighting situations.
FE stands for flash exposure. FE-Lock is especially useful when shooting reflective surfaces, which can confuse the flash metering, or when the subject doesn’t have a clear focus point. On some cameras, FE-Lock lasts for about 15 seconds, or as long as you keep the shutter button half-pressed.
Many DSLR cameras do not have a dedicated FE Lock button. Instead, the FE Lock function is linked to AE Lock. Some higher-end DSLRs have a separate FE Lock button, and others allow you to assign FE Lock to a custom function button.
