Above and right: These two pictures show how you can alter the effectiveness of the background, and so the overall composition, by changing from wideangle to telephoto. In the bottom picture a 28mm wideangle was used, and the background looks very far away. In contrast the picture above was taken with a 200mm lens from the same position: the background has been brought forward and the contours of the mountain make a far more interesting background.
With digital SLR cameras the choice of lenses is enormous and at the telephoto end of the range, lenses as long as 1200mm are available. With such a narrow field of view, ultra telephoto lenses might have their limitation, but for wildlife, sports and certain aspects of fashion photography they are in a field of their own. Telephoto lenses longer than 200mm tend to be very expensive and, unless you are going to specialise in one of the above areas, they are probably beyond the pocket of most amateur photographers. But if there is an occasion when the use of one is essential, they can be hired from a pro supplier such as Calumet.
One of the advantages that telephoto lenses have is their ability to ‘compress’ your picture. This means that the space between what is close to the camera and what is far away diminishes. This can be used to enhance the compositional qualities of your shots, as can be seen here in this shot of the old San Francisco in the foreground and the newer Downtown area in the distance. I took this using a 400mm lens. The greater the focal length, the more the perspective will be compressed.
The most important thing to look out for when using a long telephoto is camera shake. A good rule of thumb is that if you are using a lens with a focal length of 100mm you should be using a shutter speed of at least 1/125th second. On the other hand, a lens with a focal length of 200mm will require a shutter speed of 1/250th second and so on. If you do not have a lens with an image-stabilising mode then you will have to support it in some way. An alternative to a tripod could be a monopod. This is the preferred choice for many pro sports photographers. In most cases longer lenses will require larger filters as the front lens element can increase dramatically, especially with fast lenses. Because of this, some ultra telephotos have a system for slip-in filters nearer to the camera body.
While many photographers will be using zoom lenses, consideration needs to be given to the ‘speed’ of the lens. This refers to the maximum possible aperture and not the shutter – though there is a correlation between the two. A lens with a maximum aperture of f2.8 will be faster than a lens that has only a maximum aperture of f5.6. Many zooms have a maximum aperture of f3.5 when the lens is at its widest focal length, but becomes f5.6 when zoomed to telephoto. This will necessitate using a slower shutter speed (which could result in camera shake) or increasing the ISO (which might result in an increase in noise). While these lenses can be moderately priced, the quality will always be inferior to a lens with a fast maximum aperture throughout its focal lengths.