OK this photo was a bit hard to do. I have been wanting to try Zack Arias technique for blowing out the background. I have an sb600 at full pwr just to the right and behind the subjects at the bg (my studio wall). Subjects are sitting on a piece of whiteboard and are lit with a Sunpak383 just left of cam @ 1/8 pwr... took a bit to dial in. Started with the key light and subjects... then did the bg... luckily full pwr was enough for my little speedlight :) to blow it out white