#Y2024 #摄影 [相机与测光表，相伴过百年，它们又有怎样的故事？](https://www.163.com/dy/article/H5EHFCES0524DLT3.html) - 钟表计时 - 感光板变色测光 - 表格式测光表 - 消光式测光表 - 硒测光表 - CDS测光表 [[硒测光表]]selenium light meter  A selenium meter is a light-measuring instrument based on the photoelectric properties of selenium. The most common use of such light meters is measuring the exposure value for photography. The electric part of such a meter is an electromagnetic measuring instrument which is connected to the anode and cathode of a selenium photo cell that produces more or less electric power when exposed to more or less light. The optical part of such a meter is a window in front of the photo cell's light-sensitive side. The window's surface is usually structured like a honeycomb made of convex lenses. This type of window helps to bundle the light coming from the direction in which the photo cell is pointed. The mechanical part of a selenium meter is an analog calculator which accepts exposure value and film speed as input parameters for showing the possible aperture and shutter-speed combinations for correct exposure.