1 light or 2

Setting: the family is on the rug reading and working on homework
Lighting: evening, so just some mild fluorescent bulbs above subjects
Thoughts: they are low to the ground and I don't want to pull out the umbrellas and the light stands. So I grab the reflector (silver/gold side out for neutral warmth) and grab an SB600 flash with the little plate it comes with for setting down on the ground. I place the SB600 in front of the reflector, pointing directly away from my subjects. Then I grab my SB800 with the diffuser on it and put it on my camera. I am actually about 12 feet away from my subjects, but the SB600 is about 5 feet from them.



Settings: the SB600 is set at TTL (through the lens- basically, this is auto setting, and the camera decides what power to put through it). I've got a long lens on to get close in (shooting from 160mm to 200mm) I am also shooting at f2.8 and 1/80. I chose 2.8 because I am trying some focal depth experiments with my long lens and it lets my flashes work at a lower power. I chose 1/80 because anything slower seems make my subjects movement show up (out of focus).
The SB800 is on 1/124 power (so virtually nothing... just used to fire the SB600) and because I am so far from my subjects, I am essentially just using one flash here.
Fire a couple of shots...


I like the focus on my subjects, but the background is really dark... too dark.
So I increase the power of the SB800 to about 1/2 power (really get some ambient light around them). No other settings changed. (I could have just changed my exposure to 1/20 or 1/15 instead of 1/80, but then I risk out of focus subjects, esp the spontaneous pics I was shooting). Or I could have increased my ISO to 1600, but that's really going to make it grainy with my camera.
So a couple of shots...


So I like the fill light that brought my images.
Parting shot... I really like this one because I like broken light, when it finds its way to your subject