Interchangeable lenses add great fun to digital photography.
A lens uses optics to record light in the form of an image to a digital camera's sensor. One of the most exciting aspects of advancing to a single-lens reflex (SLR) camera is exploring the available interchangeable lens possibilities. SLRs are usually sold as a package with the camera body and a designated lens; however, you may choose to purchase only the body and select a different lens that has a wider application. Basic choices (or focal lengths) include wide, normal and telephoto lenses, each of which may be either prime or zoom models.
Wide-angle
Wide-angle lenses can capture a unique perspective.
Wide-angle lenses have a short focal length and capture a broad area of view. A short focal length translates into great depth of field, meaning that almost everything in the image--from foreground to background--can be in sharp focus. While wide-angle lenses are recommended for shooting landscapes, they may also be used to capture close subjects. The resulting photo will have a unique perspective.
Telephoto
Shooting with a telephoto lens allows you to blur out the background.
Telephoto lenses, which have a long focal length, employ optics to bring your photo subject closer. A long focal length translates into short depth of field, meaning that often only your subject will be in focus and the background will appear blurred. Blurred backgrounds offer a great way to accent your subject and de-emphasize any busyness in the image. Telephoto lenses, available in moderate and super-long focal lengths, are recommended for portrait work, sporting events and wildlife photography.
Prime or Zoom
A zoom lens offers greater flexibility.
A prime lens may be either a wide-angle or telephoto lens, but it has a fixed focal length, as in 100 mm. A zoom lens may be a wide-angle lens or a telephoto lens, or it may range from wide-angle to telephoto; however, it has a variable focal length, as in 18 mm to 270 mm. According to Photography.com, "A zoom lens allows the photographer to widen or shorten the lens' focal length to increase or decrease the magnification of the subject." While prime lenses can result in a sharper image, zoom lenses offer the photographer greater flexibility. Lense manufacturers will also package macro (or extreme close-up) capabilities with either prime or zoom lenses.
Lens Speed
Faster lenses are desirable when shooting in low-light situations.
Another consideration when selecting wide versus telephoto or prime versus zoom is the speed of the lens. The speed of a lens is determined by its largest f-stop, or lens opening. A large f-stop (as in f1.2, f1.4, f1.8 or f2) allows more light to reach the camera's sensor, which, in turn, gives the photographer extended options when shooting in low-light conditions. Faster lenses equate to higher prices.
Research
Test a lens before making a purchase.
Your application (portrait work, close-ups, landscape photography, wildlife shots, etc.) and budget will dictate which lens you ultimately decide to buy, but thorough research will ensure a quality purchase. Internet and print material such as "Consumer Reports" offer a variety of sources detailing both expert and consumer reviews. In order to make a sale, many camera stores will allow photographers to test a lens in the store and then evaluate the resulting photos at home. Firsthand experience is hard to beat when choosing a lens.
Tags: focal length, telephoto lens, zoom lens, camera sensor, depth field