f-number

英/ ˈef nʌmbə(r) /

美/ ˈef nʌmbər /

1
焦比
...从成像端往镜头看去可以看到光形成的圆的直径光圈值 - 摄影知识 Wiki - Wikia 在光学中，一个光学系统中的焦比(英文f-number，或称"F比例"、"相对孔径"、"光圈值"等)表达了镜头的焦距和光圈直径大小的关系。简单来说，焦比等如焦距数除以孔径数。
2
光圈值
尺度的光圈值（f-number）的编号如下：事实上单反相机。
3
焦距比数
...议直接在su调节物理摄像机：调节快门＼焦距比和ISO，让场景更快“亮”起来 1快门速度(shutter speed)： 2焦距比数(f-number)：相机的光圈，值越小，光孔越大 3ISO感光度(film speed ios)：值越大，场景越亮，噪点越多。

短语

1
The matric characteristics and convergences on F-number space are investigated.
探讨了F数空间的度量特征及几种收敛性的关系。
2
The aperture size (area of the aperture) of a lens could be calculated from focal length and the correspondent f-number.
光圈孔的大小，可从镜头的焦距与焦距比数中计算出来。
3
The elapsed time for completing the task becomes a function of the partition size f(1,000,000) versus a function of the total number of records to process f(100,000,000).
完成这项任务所耗的时间变成为分区大小的函数 f(1,000,000)，而不再是要处理的总记录数的函数 f(100,000,000)。

F-number
In optics, the f-number (sometimes called focal ratio, f-ratio, f-stop, or relative aperture) of an optical system is the ratio of the lens's focal length to the diameter of the entrance pupil. It is a dimensionless number that is a quantitative measure of lens speed, and an important concept in photography. The number is commonly notated using a hooked f, i.e. f/N, where N is the f-number.

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