telephoto lens
telephoto lens
(ˈtɛlɪˌfəʊtəʊ)tel′epho′to lens′
n.
Noun | 1. | telephoto lens - a camera lens that magnifies the image |
单词 | telephoto lens | |||
释义 | telephoto lenstelephoto lens(ˈtɛlɪˌfəʊtəʊ)tel′epho′to lens′n.
telephoto lenstelephoto lensTelephoto Lensa photographic lens with a focal length that is longer than normal, in which the distance between the front surface of the first lens and the back focal plane is shorter than in other types of long-focus lenses. This feature permits a reduction in the overall size of still and motion-picture cameras. Telephoto lenses are used in producing large-scale photographs of distant objects and for portraits. The most common designs for telephoto lenses make use of two components (Figure 1), each consisting of a group of lenses; the first group is a converging system, and the second is a diverging system. The components are combined in such a way that the back principal plane H’ is moved forward of the lens and the distance L is shortened. The shortening index Kt = L/f′ In some telephoto lenses, the focusing distance of the second group of lenses is positive, and Kt is close to unity. Such lenses are considered three-group systems. L. A. RIVKIN telephoto lens[¦tel·ə¦fōd·ō ′lenz]telephoto lens
Synonyms for telephoto lens
|
|||
随便看 |
|
英语词典包含2567994条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。