One of the distinctive attributes of a telephoto lens is it's ability to compress elements. This allows two elements to be juxtaposed in the same frame as in this picture of Chrysler CEO Sergio Marchionne.
Whether it be a moderate telephoto zoom like the 80-200 mm or a large, super-tele like the back-breaking 600 mm, telephoto lenses have often been associated with sports or wildlife photography.
But several distinctive attributes make these long lenses useful tools in a variety of photographic situations.
Of course the most obvious characteristic of a telephoto lens is the magnification factor. This is helpful when practicality dictates that you can't get close to your subject; these long lenses will allow you to reel in distant subjects and will bring you in closer to the action.
This also makes the telephoto lens an effective tool for getting great candid photos of people. By standing back from the action the photographer can shoot from a distance and remain inconspicuous while capturing all those natural moments and expressions.
But it isn't just their ability to magnify distant subjects that make long lenses useful. For instance, a shallow depth of field created by using a telephoto lens combined with a wide aperture - say F2.8 or F4 - will allow the subject to be tack sharp while the background quickly falls out of focus.
This technique known as 'selective focus' will help to isolate your subject and is a great way of separating your subject from a busy or distracting background. It's used often in portrait photography.
Compression is another trait of the telephoto. While a wide angle lens tends to stretch out perspective and add a sense of depth to an image, a telephoto lens will have just the opposite effect. By compressing visual elements telephotos can be particularly handy when trying to put two elements together in the same frame. At press conferences, photographers will often use this technique to juxtapose a CEO with the company logo or some other graphic element.
However, there are some things to keep in mind when shooting with long lenses.
Due to the shallow depth-of-field inherent in these long lenses the photographer must take extra care when focusing. Even just a slight error in focusing can cause a subject to be soft and ruin an otherwise great image.
Also, because camera shake (blur caused by an unsteady camera) can be a problem particularly when shooting hand-held with long telephoto lenses, it is advisable to use a higher shutter speed to compensate for this.
If necessary set your camera to a higher ISO to allow for these higher shutter speeds.
Also, it's advisable to use a tripod or monopod when shooting with long lenses. Not only will this take strain off your back and shoulders while trying to hold a heavy lens for long durations but it will also help reduce camera shake.
Although quite expensive, a good telephoto lens can be an important addition to your kit whether shooting candid photos at a family wedding or capturing the winning goal at your son or daughter's soccer match.
Have fun and good luck.