The lens that you put on your camera is almost as important as the camera body. Some may argue that the lens is more important than the actual camera. There are many different types of lenses, from ultrawide-angle lenses to super-telephoto lenses. The lens that you use depends on the subject you're photographing, as well as how you want the subject to appear in your images. The different types of lenses all have an impact on the way the subject looks to the viewer. You have a lot to consider when purchasing a lens, whether it's a zoom or prime lens, a wide-angle or telephoto lens, or any of the numerous other options. The goal of this chapter is to give you a head start on knowing what kind of lens you want before you actually start looking.
The ability to use a variety of lenses is one of the main advantages of using a dSLR camera.
One thing you need to remember before purchasing a lens for your D3000 is that only Nikon AF-S (or the third-party equivalent) lenses autofocus with the D3000. Until recently, all Nikon AF lenses were focused by a screw-type motor in the camera body. Most high-level cameras have this focus motor, but some models leave it out to make the cameras more compact; the D3000 is one such model.
Sigma's AF-S equivalent is termed HSM for Hyper-Sonic Motor.
AF-S lenses are focused by an internal mechanism ...