Samsung Galaxy NX500 Camera User Manual (en)

My Camera > 
Shooting modes
 Shutter Priority mode
In Shutter Priority mode, the camera automatically adjusts the aperture 
value according to the shutter speed you choose. This mode is useful for 
capturing photos of fast-moving subjects or for creating tracer effects in a 
For example, set the shutter speed to over 1/500 s to freeze the subject. To 
make the subject appear blurred set the shutter speed to below 1/30 s.
Slow shutter speed
Fast shutter speed
Rotate the mode dial to S.
Scroll command dial 1 or command dial 2 to adjust the shutter 
You can also assign other functions to command dials 1 and 2. 
(p. 177)
You can also adjust the shutter speed by pressing [f], moving to 
the shutter speed, and then scrolling command dial 1 or dragging 
your finger on the screen.
Set the desired options.
Half-press [Shutter] to focus, and then press [Shutter] to 
capture the photo.
To compensate for the reduced amount of light allowed by fast shutter speeds, 
open the aperture and let in more light. If your photos are still too dark, increase 
the ISO value.