I got a Nikon D3000. I love it and it takes really nice pictures. This week I got a new lens (the 55-200mm) and since i am an avid horseback rider, I decided to try it out and take some pictures of my friends at my barn jumping their horses. Nearly every picture I took got blurry in the motion. How can I fix this and do you have any action-shot tips for me and my new camera?