Instructions
Turn your camera on, and set the exposure mode to manual. Set the ISO (light sensitivity) to 400. Do not use an automatic exposure because the camera will want to make the pictures much brighter than what is needed. If the dancers are performing under spotlights, the camera will set the exposure so the dancer is over-exposed unless you meter correctly.
Hold the camera to your eye and press the asterisk button to spot meter the brightest and darkest points on the stage. Do this when the spotlights are being used. Select an exposure that is the midway point between these two readings. Set your exposure, and start concentrating on the dancing.
Turn the autofocus mode to "Servo" or "Continuous." This ensures that as long as you keep the shutter release button halfway down, the camera will track and keep the dancer in focus. This quickens the camera's response time when you press the shutter button fully to take the picture.
Hold the camera to your eye, press the shutter release halfway down and track the dancer you want to photograph. When the dancer performs, press the shutter release to take the picture.