Nikon D3X User Manual page 218

The SB-900, SB-800, SB-600, and SB-400 provide red-eye reduction in red-
eye reduction and red-eye reduction with slow sync modes, while the
SB-900, SB-800, SB-600, and SU-800 provide AF-assist illumination when
the conditions for AF-assist illumination are met. When used with AF
lenses with focal lengths of 17–135 mm, the SB-900 provides AF-assist
illumination (active AF-assist illumination) for all focus points; note,
however, that autofocus is available only with the following focus points:
17–19 mm
When used with AF lenses with focal lengths of 24–105 mm, the SB-800,
SB-600, and SU-800 provide AF-assist illumination to assist autofocus for
the following focus points:
24–34 mm
In programmed auto, the maximum aperture (minimum f-number) is
limited according to sensitivity (ISO equivalency), as shown below:
100
4
l
For each one-step increase in sensitivity (e.g., from 200 to 400), aperture is
stopped down by half an f-stop. If the maximum aperture of the lens is
smaller than given above, the maximum value for aperture will be the
maximum aperture of the lens.
When an SC-series 17, 28, or 29 sync cable is used for off-camera flash
photography, correct exposure may not be achieved in i-TTL mode. We
recommend that you choose spot metering to select standard i-TTL flash
control. Take a test shot and view the results in the monitor.
In i-TTL, use the flash panel or bounce adapter provided with the flash
unit. Do not use other panels such as diffusion panels, as this may
produce incorrect exposure.
192
20–105 mm
35–49 mm
Maximum aperture at ISO equivalent of:
200
4.8
106–135mm
50–105mm
400 800
5.6 6.7
1600
8