Nikon D100 Product Manual - Page 84

Focus 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 selected 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. Taking Photographs-Focus 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 24-85 mm f/2.8-4.0 • AF-S ED 17-35 mm f/2.8 • AF 24-120 mm f/3.5-5.6 • AF ED 18-35 mm f/3.5-4.5 • AF-S ED 28-70 mm f/2.8 • AF 20-35 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 Speedlight 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. 72