Nikon D100 - Manual (Page 84)

Taking Photographs—Focus
Focus
72
The AF-Assist Illuminator
The built-in AF assist illuminator enables the camera to focus even when the
subject is poorly lit. To use the illuminator, the camera must be in single-servo
AF with an AF-Nikkor lens attached, and the center focus area must be se-
lected or closest subject priority in effect. If these conditions are met and the
subject is poorly lit, the illuminator will light automatically to assist the autofocus
operation when the shutter-release button is pressed halfway.
For the AF-assist illuminator to function correctly, the lens must have a focal
length of 24–200 mm and the subject must be in range of the illuminator.
With most lenses, the illuminator has a range of about 0.5–3 m (1´8˝–9´10˝).
With the following lenses, the illuminator can not be used at ranges of under
1 m (3´3˝):
• AF Micro ED 200 mm f/4
• AF-S ED 17–35 mm f/2.8
• AF ED 18–35 mm f/3.5–4.5
• AF 20–35 mm f/2.8
• AF 24–85 mm f/2.8–4.0
• AF 24–120 mm f/3.5–5.6
• AF-S ED 28–70 mm f/2.8
• AF Micro ED 70–180 mm f/4.5–5.6
The built-in illuminator will not light when used with the AF and AF-S ED 80–
200 mm f/2.8 and AF VR ED 80–400 mm f/4.5–5.0.
If an optional SB-series 80DX, 50DX, 28DX, 28, 27, 26, 25, or 24 Speedlight
is used, the camera’s built-in AF-assist illuminator will turn off and the Speed-
light illuminator will be used instead. With other Speedlights, the camera’s
built-in AF assist illuminator will be used.
Continuous Use of the AF-Assist Illuminator
After the AF-assist illuminator has been used for several consecutive shots, it may turn
off briefly to protect the lamp. The illuminator can be used again after a short pause.
Note that the illuminator may become hot with continuous use.
22—AF Assist ( 158)
This option can be used to turn the AF-assist illuminator off.