Nikon D200 D200 User's Manual - Page 68

Reference-Focus The AF-Assist Illuminator The built-in AF assist illuminator enables the camera to focus even when the subject is poorly lit. The camera must be in focus mode S (single-servo autofocus), an AF-Nikkor lens must be attached, and the center focus area or focus area group 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. 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. Lens hoods should be removed. With most lenses, the illuminator has a range of about 0.5-3 m (1 ft. 8 in.-9 ft. 10 in.). With the following lenses, autofocus with AF-assist illumination is not available at ranges under 0.7 m (2 ft. 4 in.): • AF Micro ED 200 mm f/4D • AF-S VR ED 24-120 mm f/3.5-5.6G • AF-S ED 28-70 mm f/2.8D • AF Micro ED 70-180 mm f/4.5-5.6D With the following lens, AF assist is not available at ranges under 1 m (3 ft. 3 in.): • AF-S DX ED 55-200 mm f/4-5.6G With the following lenses, AF assist is not available at ranges under 1.5 m (4 ft. 11 in.): • AF-S VR ED 70-200 mm f/2.8G • AF-S ED 80-200 mm f/2.8D • AF ED 80-200 mm f/2.8D With the following lens, AF assist is not available at ranges under 2.5 m (8 ft. 2 in.): • AF VR ED 80-400 mm f/4.5-5.6D AF assist is not available with the AF-S VR ED 200-400 mm f/4G. 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. a9-AF Assist ( 152) 58 This option can be used to turn AF-assist illumination off.