Also, concentrate on optical zoom, not digital zoom, which degrades image quality.
另外还要注意光学变焦，而不是数码变焦，数码变焦会降低画面质量。
It's just a pity that the handset is short on memory and doesn't have an optical zoom component.
这只是可惜的是，手机是对短期记忆和不具备光学变焦的组成部分。
Zoom optical systems have been widely used on all kinds of optical instruments, and more and more new design methods have been employed.
变焦距光学系统已经在各种光学仪器上获得了广泛的应用，一些新的设计思想也层出不穷。
Zoom optical systems have been widely used on all kinds of optical instruments, and more and more new design methods have been employed.
变焦距光学系统已经在各种光学仪器上获得了广泛的应用，一些新的设计思想也层出不穷。
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