Читать книгу Collins Complete Photography Manual - Collins Dictionaries - Страница 95

 Wildlife photography is difficult or impossible without telephoto lenses, since animals and birds frighten easily if you get too close.

 Many sports are impossible to photograph successfully without a telephoto lens because spectator areas are a long way from the action.

 Telephoto lenses can produce striking landscape shots, since they enable you to pick out distant details and ‘flatten’ perspective.

 Portrait shots can be improved by throwing backgrounds out of focus. This requires shallow depth-of-field, a characteristic of telephoto lenses.

To find the minimum safe shutter speed, divide 1 by the focal length being used. With a 200mm lens, this gives a shutter speed of 1/200sec. Although most of the time this works, there is no absolute guarantee of sharpness and it may still be possible to see camera-shake at 1/400sec.

Some telephoto lenses have image-stabilization mechanisms which move elements within the lens to counteract any movement during the exposure. These can help you get sharp shots and shutter speeds two to four times slower than normal.