How do I tell my SB-800 that I only want fill? This weekend I was able to get out and shoot outside for the first time since getting my Nikon gear and couldn't get my SB-800 to do fill very well. With Canon it was easy ... if you wanted the flash to be primary light source, you set your body into Program mode (P), the camera would snap the shutter speed to 1/60th of a second at that point, use the dial to adjust aperture to liking. If you wanted the flash to act as fill, leave the camera in either Av or Tv, put the flash into high-speed sync mode, and start shooting. How do I get my Nikon gear to do "fill"?