“On-Camera” Versus “Remote”
You can take pictures using a flash unit mounted on the camera accessory shoe or one or more remote flash units.
Camera-Mounted Flash Units
Take pictures using a flash unit mounted on the camera ( Using an On-Camera Flash ).
Remote Flash Photography
Take pictures with one or more remote flash units using wireless flash control (Advanced Wireless Lighting, or AWL) as described in “Remote Flash Photography” ( Remote Flash Photography ).