Samsung Galaxy NX500 Camera User Manual (en)

Concepts in Photography
DOF preview
You can press the Custom button to get an idea of what your shot will look 
like before shooting. The camera adjusts the aperture to the predefined 
settings and shows the results on the screen. Set the function of the 
Custom button to Optical Preview. (p. 174)
The way that objects are arranged in a photo is referred to as its 
composition. A good composition emphasizes the photo’s subjects 
by drawing attention to them and by balancing them with the other 
elements in the photo.
Following the rule of thirds is one method that usually results in good 
Rule of Thirds
To use the rule of thirds, divide the image into a 3x3 pattern of equal 
To compose photos that best emphasize the subject, make sure the 
subject is located at one of the corners of the center rectangle.