focal ratio

focal ratio

美 　英

• 網絡焦比；焦距比；焦比大

例句

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，你還可以將目鏡的焦距除以望遠鏡的焦比來得到出瞳尺寸。

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（focalratio），你可以通過這樣計算的得到焦距：孔徑（單位是mm）乘以焦比就是焦距。