I was shooting in a covered arena, where there is ambient light. In speaking with the woman I shoot for, this is much more problematic than an indoor arena where the entire sides of the arena aren't backlit. Even with the overhead lights on during the day, trying to shoot at 1/640 @ f/6.3 min requires an ISO so high as to render the images unsellable in my boss' POV. Since I shoot for her, changing this isn't an option.
So, I guess the lights are for "fill". In the test gallery, I included night shots from both cameras, as well as day shots...with the 2 light setup we used during the night shoot, and the 3 light set up we had when we started seeing some motion blur in her camera, but only when the sun came out from the clouds after a weekend of heavy rain.
I have a D300s rented and arriving on Wednesday. Since I need to set up Friday afternoon, I'll have a chance to shoot the D600 again, and will lower the power from 1/1 to...what would you suggest...halfway between 1/1 and 1/2, perhaps? If that doesn't work, I'll likely bump the lights back up and try with the D300s, with it's faster shutter speed of 1/250.
For what it's worth, I attempted to shoot @ 1/250 on my D600 during the day, and got a dark band at the bottom, meaning it wasn't synching correctly. I shot a complete day's show (different show) using her Canon 7D @ 1/640...before I realized that the synch thing was an issue. Same set up, essentially, covered arena. Only the top 1/4 of the frame was lit, becoming more apparent as the daylight waned. So I kept bumping ISO. Once I realized my error...after that day's show..I walked back to the arena, dialed it back to 1/250, snapped and the whole arena was lit like daytime. Lesson learned.
So, here is the test gallery
I selected these images because the settings were identical, or very close to each other. The night images were 2 AB1600s, full power w/small reflectors, 60' from barrel. The first 2 daytime images, same lighting setup. Last two images are 3 AB1600s, full power w/large reflectors, 60' from barrel.
Incidentally, of the daytime Nikon photos, those were among the best of them. Most had substantially more motion blur.
I want to thank you for all the assistance and, more importantly, patience as you help me work through this. As I said, I normally shoot with speedlights, so this is a new world to me and I'll take all the help I can get, esp since I really have gotten to like this camera.
Thanks, Tim (p.s. I didn't take your original comments as harsh at all...it takes a lot to offend me..LOL. This is one area I just didn't realize that less could be more (effective)).