If you have a D-40 and your pics are coming out blurry, it's probably not the shutter speed. You may want to try on manual settings and change the ISO to about 400, Fstop as low as it will go, probably around 4.5 or 5. If it's during the day, your shutter speed should be ok at around 1/400 to 1/600. I don't have a nikon, but I have a Canon and I never use the automatic settings. I took pics of a hockey game once with the above settings and they came out fine. It might be good to play around with those settings at a park taking pictures of people running or playing with their dogs. That sounds lame, but it's all I got!