Nikon 5700 - Manual (Page 69)

Taking Pictur
es : The Details—Using the Camera Contr
ols (All User Sets)
57
AE/AF Button: Locking Focus and Exposure
By default, pressing the AE/AF button when the camera is in focus locks
both focus and exposure. The Controls: AE-L, AF-L option in the SET-UP menu
(
131) can be used to set the AE/AF button to lock just focus or just
exposure. With focus set to lock, you can adjust exposure without refocusing
the camera. With exposure set to lock, you can refocus the camera without
adjusting exposure. You can improve results by manually selecting the center
focus area (
112) and setting metering to spot or central-weighted meter-
ing ( 103).