The picture is took during the 4 on 4 volleyball tournament. This photo is used the skill of aperture. Aperture works the same way as human eyes. When our eyes are focusing on an object, only the object that we are starring at is clear. Other like back ground will also become blurred. As you can see in this picture, the girl is hitting the ball, like we focusing on watch her hitting the ball, only her is clear, and the background is blurred.