I spent yesterday evening doing a shoot that I've wanted to do for at least 3 months.
My bud Case Frick has a BIG jeep and Flagstaff is surrounded by the largest ponderosa pine forest in the world. That means there are bunches of places for us to get out off some dirt road in the middle of nowhere. We drove 15 minutes out of downtown and found ourselves a nice secluded spot. Took off all the light covers, turned on the huge-ass lights and voila!
Low angle, 18mm ISO 2000 at 1/20 sec or so. SB600 is camera right, easily 20 feet from the jeep, 10 feet behind the camera, zoomed to 70mm and aimed right at Case's big head. The flash was at 1/128 power because of my astronomical ISO. I Had an issue for maybe 10 seconds with the SB600 not firing, but using my hand as a reflector for my pop-up/trigger, I got it to work quite well.
I moved the camera up a few feet, dropped the exposure to 1/50 sec or so. This took out some of the super-saturation and blown out highlights that make up the right side of Case's face in the first image.
I really can't pick between the two. Either way, ISO 2000 looks GREAT!