Choosing and Using Lenses

The optical elements in the lens move to compensate for camera-shake, thus producing a sharper image. In some camera systems, the image stabilization is in the camera and works for all lenses mounted on the camera. A zoom lens contains every focal length in its range. Most zoom lenses have a variable maximum aperture to keep the size and price of the lens down. A prime lens has a fixed focal length. Prime lens have fewer optical elements, which makes them less prone to lens flare, and they may be slightly sharper, but the difference is negligible. The protection filter probably won't save your lens if you drop it. A variety of split ND filters are made to solve the contrast problem. Some neutral density filters have a sharp division between the clear and dark part, others are gradual splits, and they come in different strengths to conquer various contrast problems.