I recently tried to shoot some volleyball action and was disappointed. I didn't like the lack of a crisp image of the athletes. The pro working the same gym had flashes mounted in the ceiling. I'm sure that was a big help. I wrestled with whether I should use my Nikon 600 flash with a difuser because I didn't want to be too distracting for the athletes. What are the lenses and settings most people use for basketball and other sports in a gym? What are your thoughts on using a flash?