focal length

US /ˈfoʊ.kəl ˌleŋθ/
UK /ˈfoʊ.kəl ˌleŋθ/
"focal length" picture
1.

焦距

the distance from the center of a lens or curved mirror to its focal point

:
Adjusting the focal length changes the magnification of the image.
調整焦距會改變圖像的放大倍數。
A longer focal length results in a narrower field of view.
更長的焦距會導致更窄的視野。