他看似孤身一人，事实上整条大街熙熙攘攘。只是他身旁的车流人流移动太快而无法被需要10分钟时间曝光的照相机捕捉下来。
He seems to be all alone in what was actually a busy street-the carts and the people around him were moving too fast to be fixed by the 10-minute exposure.
美国发明家萨缪尔·摩尔斯看到用达盖尔照相法拍的巴黎街景里一个人都没有时，不禁大吃一惊，后来才明白是因为曝光时间过长，移动物体都变得看不见了。
Samuel Morse was astonished to learn that Daguerrotypes of streets of Paris did not show any humans, until he realized that due to the long exposure times all moving objects became invisible.
夜间摄影需要长时间曝光，这就意味着月亮可能会在曝光期间有很明显的移动。
The long exposure time required for moonlight photography often means that the moon may have moved significantly over the course of the exposure.
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