Samsung Digital Camera User Manual (en)

Basic functions
        Preventing your subject from being out of focus  
It may be difficult to get your subject in focus when:
 There is little contrast between the subject and background. 
(For example, when your subject is wearing clothing that is similar in color 
to the background.)
The light source behind the subject is too bright.
The subject is shiny.
The subject includes horizontal patterns, such as blinds.
The subject is not positioned in the center of the frame.
Use the focus lock
Half-press [Shutter] to focus. When the subject is in focus, 
you can reposition the frame to change the composition. 
When you are ready, press [Shutter] to take your photo.
When you take photos in low light
Turn on the flash. 
(p. 50)
When subjects are moving fast
Use the continuous 
or motion capture 
function. (p. 64)