5X, 2X, or 3X. This designation tells you what the new focal length will be once
the lens is attached to your camera. If it is a 2X lens, for instance, the lens will double the focal
length of your camera. Obviously, a 2X lens is a telephoto, and attaching it to a typical digital
camera should yield a focal length in the vicinity of 200mm.
If you are looking for a wide-angle lens, shoot for one that has an X power of less than 1.
Suppose you purchase a .6X lens. When you attach it to your digital camera, it will reduce the
focal length by 40 percent. Zoomed out at a focal length of 40mm, your camera will actually
provide a focal length of 24mm, which is rather wide. If you zoom in to your camera??™s telephoto
position, the add-on lens will still work. Now, your usual 100mm will only be 60mm.
You can sometimes purchase add-on lenses in a complete set, such as the one in Figure 8-3.
FIGURE 8-3 A collection of add-on lenses that all fit common digital cameras
162 How to Do Everything: Digital Camera
Add-On Lens Precautions
While add-on lenses are a powerful tool for expanding your photographic options, you need to
take some care to avoid an effect known as vignetting. Vignetting is what happens when the lens
barrel itself gets into the picture, causing the frame to lose its square shape.
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