像摄录机这类产品的维修要求用户电子技术员获得一些传统实践中电子领域以外的知识,和学习一些有关光学、聚焦、曝光等这类知识。 为了使摄录机更容易使用和对用户更有吸引力,摄录机厂家增加了自动聚焦系统,从而让使用者不必操心聚焦问题。然而,摄录机上自动聚焦的存在又意味着摄录机技术员又必须操心自动聚焦:它的构成如何?又如何工作?又可能如何出毛病?如何维修? Maintenance of such products as video cameras requires the user’s electronic technician to acquire knowledge outside of the electronics field for some traditional practices and to learn about such things as optics, focusing, exposure, and the like. To make the camcorder easier to use and more appealing to users, the camcorder manufacturer added an autofocus system so users do not have to worry about focusing problems. However, the presence of autofocus on the camcorder means that camcorder technicians must also focus on autofocus: how does it work, how it works, how it can go wrong, how can it be repaired?