8的光圈值会使背景的树啊灌木啊如牛奶般柔滑，不过同时也可能把站在最边上的大叔拍模糊了。

An aperture of 2.8 might make the trees and shrubbery look silky smooth, but it might make Uncle Bob at the end of the line look fuzzy.

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人像模式用一个大光圈(f值小)，而让景深(清晰对焦的那部分)变小。

Portrait mode chooses a large aperture (a small 'f' number) which will make the depth of field (the amount of your shot in focus) smaller.

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你还需要根据风暴的位置远近设置好适度的快门速度和光圈值。

You also need to set the proper film speed and aperture. This will all depend on location of the storm.

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