This was shot at f9 at 1/160 Second with a Norman P808 pack at full power running on a battery inverter. The rest of the images were shot with the same flash. I tried a Norman P404 pack, but it was just too weak to darken the background. The P404 is a much lighter load on the inverter, but the P808 works. The flash was a Norman LH2400 head with a 5" reflector and barn doors to narrow the light to a strip. The barn doors aren't as sharp as two flags placed in front of the flash, but they are easier to set up or move. This exposure is roughly 2-2/3 stops below the ambient exposure. Not enough to really darken the background.The nature of the bridge makes it hard to see the pattern of light, since most of it passes between the bridge rails. A lot of the power of the flash is lost hitting the barn doors.