I touch on special-purpose lenses in this chapter and describe them in more detail in other chapters in this book. Just to make things neat and tidy, I list the special kinds of lenses you may encounter (or want to acquire). They include
Optical image stabilization: I have discussed image stabilization here. these lenses counter camera or photographer shake by shifting lens elements around just before exposure. They give you the power to shoot at shutter speeds about 4 times as long without producing camera- induced blur. Sony, Olympus, and Pentax build the anti-shake feature into the camera itself, so, with only a couple exceptions, you can use image stabilization with all your lenses.
Perspective control: These optics shift to provide improved perspective when you photograph buildings or other subjects that converge in the distance.
Macro: Prime or zoom lenses designed especially for close-up photo- graphy, offering extended focusing; better sharpness; and often, extra-small apertures (such as f/32 or f/45) to maximize depth-of-field.
Focus control portrait: Nikon offers a series of DC lenses that have defocus control, which lets you adjust how the out-of-focus background appears in portraits or similar kinds of single-subject pictures.
UV: If you’re a scientist photographing subjects by using ultraviolet (UV) light, you probably want to scrounge around for one of these rare, expensive optics that don’t filter out UV in the same way that lenses built of conventional glass elements do.