Samsung Galaxy NX500 Camera User Manual (en)

Shooting Functions > 
AF area
Zone AF
The camera focuses only on the area that you set. The focus area remains 
locked on the set area even when the subject leaves the focus area. This 
mode is recommended for when you want to fix the focus on the specific 
To resize or move the focus area, in Shooting mode, press [o].
Multi AF
The camera displays a green rectangle in places where the focus is set 
correctly. The photo is divided into two or more areas, and the camera 
obtains focus points in each area. This mode is recommended for taking 
photos of scenery.
When you press [Shutter] halfway, the camera displays the focus areas as 
shown in the photo below.