如果我想要拍摄背景暗下来，只要把拍摄模式转盘转到P程序模式拍照就可以了，不需要其他任何改动。

If I do want a shot with the background dark simply move the dial back to "p" mode and fire away. Nothing else needs to be adjusted.

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第一要义就是差异(对比)：链接要足够暗(或者亮)以和背景色相对照。

The first consideration is contrast: links have to be dark (or light) enough to contrast with the background color.

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结果是这些背景星系的多重影像被扭曲成长而暗的弧——透镜效应的例子，类似于透过酒瓶底的玻璃看远处的街灯。

As a result, multiple images of these background galaxies are distorted into long faint arcs — a simple lensing effect analogous to viewing distant street lamps through a glass of wine.

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