Nikon 17002 manual Getting Good Results with Autofocus, AF lens focal length Normal frame 11 areas

Under the conditions described above, the optional SB-800 and SB-600 Speed- lights and SU-800 wireless Speedlight commander will provide active AF illumi- nation for the following focus areas:

AF lens focal length Normal frame (11 areas) Wide frame (7 areas)

23–34 mm

35–70 mm

71–105 mm

With other Speedlights, the camera AF assist illuminator will be used.

Getting Good Results with Autofocus

Autofocus does not perform well under the conditions listed below. If the cam- era is unable to focus using autofocus, use manual focus (60) or use focus lock ( 56) to focus on another subject at the same distance and then recompose the photograph.

There is little or no	The focus area
contrast between	contains objects at
the subject and the	different distances
background	from the camera

Example: subject is the same color as the Example: subject is inside a cage. background.

The subject is dom-	The focus area
inated by regular	contains areas of
geometric patterns	sharply contrasting
	brightness

Example: a row of windows in a skyscraper. Example: subject is half in the shade.

The subject appears	The subject many
smaller than the	contains fine details
focus area
Example: focus area contains both	fore- Example: a field of flowers or other subjects
ground subject and distant buildings.	that are small or lack variation in brightness.

Reference—Focus

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