I recently got myself all these flashes. i did a couple shoot last weekend for the first time using them. the location i was shooting at was really nice background was a river, with a bidge). its was around 4 PM...sun was kinda bright i used 2 vivitar 285hv. my main concern is that i was trying to get that background underexposed. since the max sync flash speed of my camera is 200, i would have needed to go at leat 1/500-600 to get the background exposed the way i wanted it exposed (underexposed a little bit). its looking good but i think its over exposed. models were not in sunlight so my flash did a really good job filling that light. i wanted to keep a shallow dept of field by shooting at f4-f5.6. i figure that the only way to get that background is to crank the aperture to at least F16 and give the flash more power? thanks for replying.