Zoom lens A lens whose focal length can be varied continuously over a substantial range.One zoom lens can replace several fixed focal-length lensed, but results are likely to be inferior.

• 变焦镜头可以把焦矩在相当大的范围内连续改变的镜头。一个变焦镜头可以代替多个固定焦矩镜头,但效果很可能比不上。