什么叫长期曝光

长期曝光，在摄影和图像处理的领域中，指的是将一个图像或物体长时间暴露在光线或射线中。这种技术通常用于某些特定的摄影效果，或者在科学研究中，例如在放射性成像或放射性标记研究中。

在摄影中，长期曝光可以创造出独特的效果。例如，长时间曝光可以捕捉到夜晚的星星轨迹，或者在静止的场景中创造出动态的效果。这种技术也可以用于拍摄流水、云雾等动态元素，使它们看起来更加柔和和自然。

此外，在科学研究中，长期曝光常常被用来观察放射性衰变或标记物的分布。例如，在生物学研究中，科学家可能会使用放射性标记的示踪剂来追踪细胞或分子的运动，而长期曝光则可以捕捉到这些标记物的分布和动态变化。

英文对照：

What is Long Exposure?

In the field of photography and image processing, long exposure refers to the process of exposing an image or object to light or radiation for a prolonged period of time. This technique is commonly used for creating specific photographic effects, or in scientific research such as in radiographic imaging or radioactive labeling studies.

In photography, long exposure can create unique effects. For example, it can capture the trajectory of stars in a night sky, or create a sense of movement in a stationary scene. This technique is also used to capture dynamic elements such as flowing water, clouds, or fog, making them appear more natural and realistic.

In addition, in scientific research, long exposure is often used to observe radioactive decay or the distribution of labeled substances. For example, in biological research, scientists may use radioactively labeled tracers to track the movement of cells or molecules, and long exposure can capture the distribution and dynamic changes of these labeled substances.