Samsung Galaxy NX500 Camera User Manual (en)

Shooting Functions > 
AF mode
Active AF
While you press [Shutter] halfway, the camera automatically detects the 
subject‘s movements and switches between Single AF and Continuous 
AF. It fixes the focus on the subject when the subject gets far from the 
camera (Single AF). It continues to focus automatically when the subject 
gets closer to the camera (Continuous AF). This mode is recommended for 
shooting subjects that are moving unpredictably.
This option is not available when the camera is recording a video.
Manual focus
You can manually focus on a subject by rotating the focus ring on the lens. 
The MF Assist function lets you easily bring a subject into focus. While you 
are rotating the focus ring, the focus area is magnified. When you use the 
Focus Peaking function, the color you selected appears on the focused 
subject. This mode is recommended for shooting a subject similar in color 
to the background, a night scene, or fireworks.
If you use this function, you cannot set Touch AFAF AreaFace Detection, and 
Link AE to AF Point options.