Locking the Exposure
You can lock the exposure when the area of focus is to be different from the exposure metering area or when you want to take multiple shots at the same exposure setting. Press the  button to lock the exposure, then recompose and take the picture. This is called AE lock. It is effective for shooting backlit subjects, etc. This feature can be used in Creative Zone modes except <M>.
 

	Focus on the subject. Press the shutter button halfway. The exposure setting will be displayed
	Press the button . The icon lights up in the viewfinder to indicate that the exposure setting is locked  (AE lock). Each time you press the button, the current exposure setting is locked.
	Recompose and take the picture. If you want to take more pictures while maintaining the AE lock, keep holding down the button and press the shutter button to take another picture.