According to the theory of optical compensated zoom, author designed optical compensated step zoom lenses.

根据光学补偿变焦距理论，作者设计出光学补偿式步进变焦物镜。

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Firstly, the zoom ratio may be enlarged. Secondly, the image point movement may be easily eliminated. The principle of optical compensated step zoom lens is explained.

这种变焦距物镜有两个优点，一是可以实现高倍率变焦，二是容易消除在变焦过程中产生的像点移动现象。

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If your subject is smaller than a car, take a step or two closer before taking the picture and zoom in on your subject.

如果拍摄对象比汽车小，则在拍摄照片前向前移一两步，然后拉近拍摄对象。

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It is one possible step along the road to pinch-to-zoom, but it is definitely not pinch-to-zoom itself.

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