Went out to the park to practice some strobe stuff. I've done this in a make shift studio in the house but was a little inspired by Zach Arias and his one light techniques. Thought I would give it a shot. SB600 full power shooting through an umbrella high camera left. ISO 100, 1/200 sec, f/7.1. Was using the D90 to sync to flash with Sigma 24-70 f/2.8-4.0. Any advice to help me improve would be greatly appreciated. A concern I have is the SB600 may not be enough power if there was more sun. If that was the case I would need a smaller aperture requiring more light. When I tried this with the 70-200 2.8 I would slow the shutter but then camera shake would be seen in the image. Thus the 24-70. I'm sticking with the SB600 regardless but is this strobe significantly less powerful than the SB900 or even SB800?