focal ratio
英
美
- n. 焦距比数
详细释义
Noun:
-
the ratio of the focal length to the diameter of a (camera) lens system
双语例句
- 1. For example, the focal length of an 8" (203.2mm) aperture with a focal ratio of f/10 would be 203.2 x 10 = 2032mm.
- 比如，孔径为8英寸(203.2mm)，焦比为f/10的透镜，其焦距为203.2x 10 = 2032mm。
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- 2. Or, you can calculate the exit pupil by dividing the focal length of the eyepiece (in mm) by the focal ratio of the telescope.
- 或者，你还可以将目镜的焦距除以望远镜的焦比来得到出瞳尺寸。
youdao
- 3. If you know the focal ratio but not the focal length, you can calculate it: focal length is the aperture (in mm) times the focal ratio.
- 如果你不知道焦距，只知道焦比(focal ratio)，你可以通过这样计算的得到焦距：孔径(单位是mm)乘以焦比就是焦距。
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- 4. When viewing extended objects, the apparent brightness seen in the eyepiece is a function only of aperture and magnification, it is not related to focal ratio.
- 当观察扩展光源时，目镜中所看到的亮度只跟孔径和放大率有关，它跟焦比并没有关系。
youdao
- 5. This is the ratio of the focal length of the telescope to its aperture.
- 这是指望远镜的焦距与其孔径的比值。
youdao
- 6. This is the ratio of the focal length of the telescope to its aperture.
- 这是指望远镜的焦距与其孔径的比值。
youdao
相关词汇
- speed 速度
- stop number 光圈数
- f number 焦距比数
【近义词】
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