As far as outdoor flash photography is concerned, the Auto FP sync found in Nikon Speedlight SB-600 and beyond can give that 'umph' and flair to the overall composure, eliminating remaining shadow that may lurk at corners. I have not gone down that road to get a SB-800/900 yet but let me do a bit more homework on what are REALLY the difference before getting one to improve my pictures.As Nikon claims, the top-of-the-range SB-900 really makes the world your studio!