Slide the focus ring to the front for autofocus.
For manual focus, slide the focus ring to the back and rotate it while checking the results in the camera display.
The focus distance and depth-of-field indicators can be used to assist manual focus. Note that manual focus may not be available in all shooting modes.
The Depth-of-Field Indicator
The depth-of-field indicator shows the approximate depth of field (the distance in front of and behind the focus point that appears to be in focus).
The camera does not display the focus distance when the lens is in manual focus mode.