Nikon D3100 2 manual 175, SB-900 AF-assist illumination is available for all focus, Shown at right

DNotes on Optional Flash Units

Refer to the Speedlight manual for detailed instructions. If the flash unit supports CLS, refer to the section on CLS-compatible digital SLR cameras. The D3100 is not included in the “digital SLR” category in the SB-80DX, SB-28DX, and SB-50DX manuals.

If an optional flash unit is attached in shooting modes other than j, the flash will fire with every shot, even in modes in which the built-in flash can not be used (l and m).

i-TTL flash control can be used at ISO sensitivities between 100 and 3200. At values over 3200, the desired results may not be achieved at some ranges or aperture settings. If the flash-ready indicator blinks for about three seconds after a photograph is taken, the flash has fired at full power and the photograph may be underexposed.

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.

If the controls on the optional SB-900, SB-800, SB-600, or SU-800 flash unit are used to set flash compensation, Y will appear in the information display.

The SB-900, SB-800, SB-600, and SB-400 provide red-eye reduction, while the SB-900, SB-800, SB-600, and SU-800 provide AF-assist illumination with the following restrictions:

• SB-900: AF-assist illumination is available for all focus

points; with 17–135 mm AF lenses, however, autofocus
is available only with the focus points shown at right.
	17–105 mm	106–135 mm
• SB-800,SB-600 and SU-800: With 24–105 mm AF lenses, AF-
assist illumination is available only with the focus points
shown at right.
With other flash units, the camera AF-assist illuminator is	24–34 mm		35–105 mm
used for AF-assist illumination and red-eye reduction.

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175