Optional flash units can be used for wireless remote flash lighting.
Advanced Wireless Lighting
A SB-910 mounted on the camera serves as the master flash. The remote flash units can be organized in up to three groups (A, B, and C), each of which can contain one or more flash units. Different flash control modes can be used for the master flash and each of the three groups.
The camera's built-in flash or an optional flash unit mounted the camera accessory shoe serves as the master flash. Disable monitor pre-flashes or choose a flash control mode that does not use monitor pre-flashes. The remote flash units, meanwhile, must all be set to a single flash mode using the controls on the flash units.
*If the camera does not have a built-in flash, use an optional SU-800 wireless Speedlight commander.