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A2: center focus point, A3: built-in af-assist illuminator – Nikon D90 User Manual

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174

L

a2: Center Focus Point

This option (available in all shooting modes) determines the size of the center focus
point.

See page 54 for more information on focus settings.

a3: Built-in AF-assist Illuminator

Choose whether the built-in AF-assist illuminator lights to assist
the focus operation when lighting is poor. This option is
available in all shooting modes except

l and m.

A

The AF-Assist Illuminator

The AF-assist illuminator has a range of about 0.5–3.0 m (1 ft. 8 in.–9 ft. 10 in.); when using the
illuminator, use a lens with a focal length of 24–200 mm and remove the lens hood.

A

See Also

See page 231 for restrictions on the lenses that can be used with AF assist.

Option

Viewfinder display

Description

c

Normal zone
(default)

Focus on stationary subjects that can be easily framed
in the focus point.

7 Wide zone

Focus on moving subjects. Not available when Auto-
area
is selected for Custom Setting a1 (AF-area
mode
).

Option

Description

On

(default)

If the subject is poorly lit, the AF-assist illuminator will light to assist the focus
operation in single-servo AF (AF-S selected for autofocus mode, or single-servo AF
selected in AF-A autofocus mode) when Single point, Auto-area, or 3D-tracking
(11 points)
is selected for Custom Setting a1 (AF-area mode) or when Custom
Setting a1 is set to Dynamic area and the center focus point is selected.

Off

The AF-assist illuminator does not light to assist the focus operation. The camera
may not be able to focus using autofocus when lighting is poor.