The second lens in a twin-lens kit is usually a telephoto zoom lens that picks up where the range of the standard zoom lens ends. These lenses take in focal lengths that are ideal for portraiture, sports and wildlife photography.
Focal lengths of 200mm or longer can emphasise a sense of layering in landscapes.
Like standard lenses, kit telephoto zooms are usually built to a price and typically cover 35mm equivalent focal lengths of 55-200mm. They also tend to be relatively compact and portable and make a versatile addition to a basic kit of camera plus standard zoom.
Telephoto Zoom Characteristics
Telephoto lenses narrow the photographer’s field of view and, in doing so, make distant subjects appear closer. Nearby objects also appear to be closer in size to more distant objects of the same size because the angle of view is reduced. This is the most common application for telephoto lenses.
Telephoto lenses are often described as ‘compressing’ perspective. However, perspective depends on where the photographer is located with respect to the subject. Using a telephoto lens probably means the subject is some distance from the camera ““ and that will influence perspective.
Rather than compressing perspective, tele lenses compress the sense of depth within a scene because more distant objects cover a larger percentage of the frame. In effect, objects at different distances from the camera appear closer together with longer lenses. The longer the telephoto lens, the closer different planes in a scene will seem to be.
This characteristic of tele lenses can be used creatively by photographers to emphasise the number of objects is a scene or to exaggerate the appearance of congestion. Be aware that very long tele lenses can make objects in a scene appear so close to each other that the scene appears static, flat and uninteresting.
A telephoto zoom lens covering focal lengths equivalent to 55-200mm enables you to tackle portraiture, sports and wildlife photography. (Source: Tamron.)
The use of a 200mm focal length reduces the sense of depth in this scene making the subjects in the foreground appear closer to the background than they really are.
It’s easier to isolate subjects from their backgrounds with longer focal length lenses, particularly when wide aperture settings are used.
Fast telephoto zoom lenses are usually large and heavy. The Tamron SP 70-200mm f/2.8 lens shown here weighs almost 1.5 kg but has the advantage of a very fast f/2.8 maximum aperture throughout its zoom range. (Source: Tamron.)
‘Fast’ and ‘Slow’ Lenses
Terms describing the ‘speed’ of a lens have nothing to do with how quickly it can focus. Instead, the term is applied to the size of its maximum aperture. Faster lenses have larger maximum apertures than slow ones.
The main advantages of fast lenses are:
1. They let more light into the camera and this will make the viewfinder image brighter (if it’s an optical finder).
2. You can shoot with faster shutter speeds in dim lighting.
3. The plane of focus at maximum aperture is often very shallow, making it relatively easy to produce blurred backgrounds.
But they have their downsides:
1. Fast lenses require a lot more glass. This makes them larger and heavier than slower lenses.
2. They tend to be more expensive.
3. The telephoto zoom lenses in the ‘kit’ category tend to be comparatively slow, with maximum apertures of f/3.5 or smaller at their shorter ends, compared with f/2 or f/2.8 for a fast lens.
Telephoto Zooms for Landscape Photography
On a landscape shoot, most photographers will reach for wide- angle lenses. However, telephoto lenses can produce some worthwhile results when shooting landscapes if you take advantage of the characteristics outlined in this chapter.
Whereas wide-angle lenses are often used to exaggerate the sense of depth in scenes, telephoto lenses can emphasise a sense of layering. This produces an impression of depth in a scene in a totally different way.
Scenes that lend themselves to this treatment tend to be composed of different layers at distinct and differing distances from the photographer.
The closest layer might comprise nearby vegetation or a door or window frame. Beyond that there may be a hillside or the houses of a village (which in themselves may be arranged in different layers). The final layers might be ridges of hills or mountains before finally there could be the ocean and/or the sky.
Depending on the clarity of the air, you might be able to take advantage of the ‘aerial perspective’ created by diffusion. Particles of dust and/or moisture in the air can refract and reflect light, reducing overall contrast and colour saturation. A progressive loss of both characteristics will emphasise a sense of distance between near subjects and the horizon, recreating a sense of depth that may have been compromised by using a telephoto lens.
Dust in the air blurs background details, adding a further sense of depth to this scene, which was photographed with a 150mm telephoto lens.
Telephoto Zooms for Portraiture
The 85mm focal length has been considered ‘ideal’ for portraiture ever since the days of film. It’s still a good portrait focal length for ‘full frame’ cameras in the digital age because it combines a natural-looking perspective with the ability to produce blurred backgrounds ““ provided the lens is ‘fast’ enough.
On cameras with APS-C sized sensors, a 50mm focal length will provide a similar perspective, while for M4/3 cameras the closest focal length is around 43mm. Users of Nikon 1 cameras should find the 30mm focal length provides a similar perspective for head-and-shoulders portraits.
A moderate telephoto lens is ideal for both candid and posed portraits because it provides a good working distance and produces a natural-looking perspective. This shot was taken with a focal length equivalent to a 105mm focal length lens on a 35mm format camera.
Some portrait photographers prefer the perspective imparted by a slightly longer lens, and longer focal lengths are usually required for candid portraits. Focal lengths equivalent to 105mm and even 135mm in 35mm format are often preferable for close-up portraits that fill the frame with the subject’s face.
Longer lenses will allow a greater distance between the camera and the subject, which may be more comfortable for subjects who are shy. But they will also compress the perceived distance between the subject and the background a little more than shorter lenses.
By 200mm telephoto lenses tend to flatten faces, which may not be flattering to some subjects. Depth compression also increases the risk of ‘choppy’ bokeh.
The main issue to consider when using a telephoto zoom for portraiture is the maximum aperture at the focal length you’re using. The widest aperture for most kit tele zoom lenses is seldom larger than f/4 and, while this can deliver out-of-focus backgrounds on a ‘full frame’ camera, it may be difficult to de-focus busy backgrounds on cameras with smaller sensors.
The smaller the sensor, the greater the depth of field for the equivalent field of view and f/stop when compared with 35mm format cameras. If you can’t avoid busy backgrounds in portraits, you’ll obtain more pleasing blurring with a ‘full frame’ camera and tele lens. With ‘DX’ and M4/3 cameras, positioning the subject well in front of the background and filling the frame with the subject may be the only solution.
Longer focal lengths ““ in this case, 120mm ““ are often best for catching fleeting expressions candid portraits because they provide a greater working distance and subjects are less aware of being photographed.
Telephoto Zooms for Close-ups
Longer zoom lenses are often used for close-ups of flowers and small insects. Indeed, some have special ‘macro’ settings for this purpose ““ although they aren’t true macro lenses. If you don’t have a true macro lens (which can produce 1:1 or ‘life size’ reproduction) these ‘macro zoom’ lenses give you a taste of macro work.
Depth-of-focus can be an issue for close-up shooting with a tele zoom lens because the maximum aperture is usually quite small. Apertures of f/5.6 are common in ‘full frame’ lenses with the 200mm focal length and can be as small as f/6.7 for 300mm lenses on a M4/3 camera.
If you can’t achieve sufficient background blurring with the widest aperture at full tele zoom, try moving the subject as far from the background as possible. If this isn’t possible, change your shooting angle to ensure the background is as even in brightness and colour as you can make it.
Many tele zoom lenses can focus close enough to allow shots to be taken of flowers and small animals.
Excerpt from Lenses Guide.