Normally, Custom Setting e3 defaults to TTL (see Screen 3 of Figure 1), which represents the single-flash i-TTL technology used by your pop-up Speedlight, or by any i-TTL compatible flash unit you put in your Nikon D200’s hotshoe. Since this article is about controlling multiple flash units, we’ll have to change that setting to Commander Mode as shown in Screen 3 of Figure 1 above.

On page 163 of the D200 manual, you will find a chart of settings that complement the Commander Mode screen. Open your manual and let’s discuss the settings. First we’ll look at the Commander Mode in TTL, which is the easiest to use, since it allows you to set exposure compensation for each of your flash Groups. Next we’ll look at M mode, since that gives you fiddly control of your flash from full-power to 1/128 power. We’ll briefly look at AA mode. Then finally we’ll consider the “--" mode, which prevents the D200 pop-up flash from firing the main flash output, but does not stop the dim monitor pre-flashes.

Special Note on Monitor Pre-Flash: For those who may not know what "monitor pre-flashes" are, here is a short tutorial. When you press the shutter release button with the flash open, the D200’s pop-up Speedlight fires several brief pre-flashes, then fires the main flash. The big flash of light you see is actually composed of several rapid pre-flashes and a big powerful flash of light. Most people don’t notice the pre-flashes, since they happen so fast. It just seems like one big blast of light. These pre-flashes fire any time your camera is set to i-TTL mode; even with single-flash use. The camera can determine a very accurate exposure by pre-flashing your subject, adjusting the exposure, and then firing the main flash pop.

Remember, you must ALWAYS raise the pop-up flash on your D200, when you are controlling multiple flash units, no matter what Commander Mode settings you use. The D200 evidently communicates with the external flash units during the monitor pre-flash cycle.

On page 165 of the Nikon D200 manual it says the following: “Position the sensor windows on the optional Speedlights where they will pick up the monitor preflashes from the built-in flash (take particular care when not using a tripod).”

Now, back to the main subject.