Nikon D800 User Manual (en)

AF-Area Mode
Choose how the focus point for autofocus is selected.
• Single-point AF: Select the focus point as described on page 96; the 
camera will focus on the subject in the selected focus point only. 
Use with stationary subjects.
• Dynamic-area AF: Select the focus point as described on page 96. In 
 focus mode, the camera will focus based on information 
from surrounding focus points if the subject briefly leaves the 
selected point. The number of focus points varies with the mode 
9-point dynamic-area AF: Choose when there is time to compose 
the photograph or when photographing subjects that are 
moving predictably (e.g., runners or race cars on a track).
21-point dynamic-area AF: Choose when photographing subjects 
that are moving unpredictably (e.g., players at a football game).
51-point dynamic-area AF: Choose when photographing subjects 
that are moving quickly and can not be easily framed in the 
viewfinder (e.g., birds).
• 3D-tracking: Select the focus point as described on page 96. In AF-C 
focus mode, the camera will track subjects that leave the 
selected focus point and select new focus points as required. 
Use to quickly compose pictures with subjects that are moving 
erratically from side to side (e.g., tennis players). If the subject 
leaves viewfinder, remove your finger from the shutter-release 
button and recompose the photograph with the subject in the 
selected focus point.