Telephoto lenses require accurate focusing since they have inherent shallow depth of field. Because their angle of view is so narrow and their weight can be considerable, a tripod is recommended to ensure continuous, accurate subject placement. Their longer focal lengths also make hand-holding the camera less of an option since shutter speeds must be fast to avoid blur from either camera or subject movement. If you use a long focal length telephoto lens, you should also use a sturdy tripod to ensure sharp pictures.
MODERATE TELEPHOTO LENSES
Moderate-length telephoto lenses (85 mm to 130 mm lenses for 35 mm cameras) can be hand-held when shutter speeds are fast enough, and are ideal for portrait work, especially headshots and head and shoulder pictures. In fact, the 105 mm is considered to be the classic portrait lens.
Even a 200 mm lens can be easily hand-held when shutter speeds exceed 1/200 second. (See Slow shutter hand holding for information on using your camera without a tripod.)
These lenses are also great for bringing landscape and cityscape details closer, and for shooting scenes from a crowd - including parades, stage shows and even your children’s Christmas pageant - when you are unable to get physically closer.
MEDIUM TELEPHOTO LENSES
135 mm to 300 mm lenses for 35 mm cameras are considered to be medium telephoto lenses, distinguishing them from moderate and super-telephoto lenses. They are right in the middle.
A fast 135 mm lens is a practical lens for candid wedding photography and for action shots when the subject is neither close nor distant, since it’s not too heavy, can easily be hand held and is great for singling out your subject. It’s a good lens for portraits, too.
The 180 mm to 200 mm lens is ideal for sports when the action is taking place just in front of you. If you are way off in the bleachers, you’ll need a more-powerful lens. Lenses in this range are also good lenses for news photography. The speed of the lens is critical at this focal length. A slow 180 mm lens will find little use, whereas a fast 200 mm lens may be your most-used candid lens since it brings the action close while allowing you to use fast shutter speeds to capture it.
A 300 mm lens does everything a 200 mm lens will do, except it brings subjects even closer. The problem with lenses in this size is that the best ones - those that are fastest - are quite expensive. We question the merits of buying a 300 mm lens for action photography when its maximum aperture is ƒ/5.6 or even ƒ/4, because the shutter speeds required are often so slow that you sometimes can’t capture fast-moving images without subject blur, even when using fast film. But, a 300 mm lens that has a very wide ƒ/2.8 maximum aperture is quite costly. Of course, if you don’t need fast shutter speeds when you use your 300 mm lens, then it needn’t be a fast lens, but the use of a tripod is essential.
SUPER-TELEPHOTO LENSES
Powerful telephoto lenses from 400 mm to 800 mm and up are expensive, even for the slower varieties, but they deliver the ultimate in telephoto photography. Deep pockets are needed for all the lenses in this range, especially the fastest versions, since a single lens can cost more than the average consumer may spend on photography in a lifetime.
A high-quality 400 mm ƒ/2.8 lens is the dream lens of many a sports and wildlife photographer, something they may save for years to purchase. A 600 mm ƒ/4 lens is even more exotic, but the 16-times magnification of an 800 mm ƒ/5.6 lens can even be used for astrophotography with sharp, colorful results.
Professional photographers are the primary users of such fabulous lenses. Many of the images we see in newspapers, and sports and action magazines are taken with these lenses.
MACRO LENSES
A macro lens may have a focal length of, say, 60 mm or 105 mm, but is differentiated from other lenses in these focal lengths by its ability to extend out a longer distance to permit focusing only a few inches from the subject. A 55 mm or 60 mm macro lens may be used as a normal lens, and a 200 mm macro lens may be used as a telephoto lens, but their ability to focus extremely closely allows macro lenses to capture images of tiny objects in frame-filling, larger-than-life sizes.
The closer your lens is to a subject, the less depth of field you will have at any given aperture. When you are extremely close, depth of field may be a fraction of an inch. You need to set small apertures, like ƒ/16, to ensure your subject will be acceptably sharp. Macro lenses usually have quite small minimum apertures in order to maximize the depth of field.
ZOOM LENS
A zoom lens allows you to change focal lengths without changing lenses. It has variable focal lengths, enabling it to be used as a wide-angle lens for one exposure, then as a normal or telephoto lens for another, depending on its range of focal lengths. Some zooms cover a range of mainly telephoto settings, from 70 mm to 300 mm, for example, or 80 mm to 200 mm, whereas others provide a selection of wide-angle focal lengths, such as 17 to 35 mm. Popular, all-around-use zooms range from moderate wide-angle to moderate telephoto.
A zoom’s range is generally indicated by its widest and narrowest focal lengths, for example 70-300 for a lens that zooms from 70 mm to 300 mm. There is often an arrow between the numbers to indicate that it is a zoom.
Zoom lenses provide the photographer with flexibility in framing images while remaining in one camera position. With a 70-300 zoom, for instance, you can take a three-quarter-length shot of someone at the 70 mm setting, a head and shoulders portrait at 105 mm, and shoot a distant wild animal at 300 mm.
The main disadvantages to zoom lenses are that they are often heavy and slow. Many have maximum apertures no faster than ƒ/4 or ƒ/3.5 at their widest focal length. High-quality, faster zoom lenses can be prohibitively expensive, if available at all for your camera model. A good quality zoom lens is of particular use in aerial photography and for speed and versatility when photographing weddings.
|
