My daughter has started racing high school mountain biking, so I've dusted off the equipment and started shooting again. I currently own a D300s with my primary lenses being an old 70-210 f4 and a 35 f1.8. The 70-210 is nice, but a little slow to focus. The 35 is primarily used for shots around camp. What lens or lenses would you suggest for this type or shooting. To add a little challenge, I may occasionally shoot a High School band or musical. Thanks in advance for any input!