景深的控制和运用

On the Control and Application of the Depth of Focus

在摄影实践中人们总是遇到这样的情况：有时需要将前景、背景同主体一样拍清晰，向观众交待环境，表现空间深度，而有时为了突出主体只需要将主体拍清晰，这就是景深的运用问题。景深一词在摄影技术中由来已久。人们或受到摄影器材的限制，或对这一概念的认识不足。在摄影中总是不能娴熟地加以运用。事实上，在摄影实践中，景深是作品表达主题思想的一个重要方面，是一个摄影者必须弄清且能灵活运用的问题。本文就景深的概念及与之间相应的关系进行简单的讨论。

In the practice of photography, one meets such cases sometimes it is needed to shoot the front view,background and the subject with the same clearness to introduce the surroundings to the audience or to show the depth of space; while it is sometimes needed to shoot the subject more clearly to give it prominence. This is the application of depth of focus. Depth of focus has long been used in the technology of photography ever since. Owing to the limitation of photographic equipment or the little knowledge of this concept, it can not be applied skillfully in photography. In fact, depth of focus plays a very important role in photography for the works to express the central ideas. It must be known clealy and applied skillfully by any photographer. This article briefly deals with the concept of depth of focus and its corresponding relationships.