Brace for Impact

I continue to explore with the "drops" series. I'm having trouble with focusing the image. This one is 1/1600th of a second at f/11 and it still is a bit soft. Although, it has better focus than some of the others. Maybe I need to push the shutter even faster? Or, maybe I'll try a non-macro lens to see what happens.

Camera = Canon 20D
Lens = Canon 100mm f/2.8 macro
Shutter = 1/1600 second
Aperture = f/11
Focal Length = 100mm
Exp Comp = 0 ev
Flash = on (580ex + 500W studio light)
ISO = 200