Impacts
Like the tennis ball photo, a sound trigger was used for this one. In this case the trigger was placed behind the ball and several feet away. The camera and flash were placed on the floor as close to the ball as the photographer dared. Since the ball was kicked in an enclosed area, a heavy canvas tarp hanging from the ceiling was used to keep the ball from rebounding. The room was not darkened completely, because the kicker had to see what he was kicking!

