测光表是摄影中用以测量光线强度的一种光电仪表。它能科学地测出光线的强弱,指出曝光时光圈与快门应有怎样的组合关系,才能使胶卷得到最佳曝光。传统的测光表都是机械式的,它们往往不能兼顾背景光和闪光测量,功能不全,而且读数也不直观,本文旨在介绍一种由单片机80C31控制的数字式测光表。其特点是不仅可以测量背景光的强度,而且可以测量以闪光灯作为光源时的光强,并能以液晶方式显示数值和符号,还可以作为一个定时器,供暗室里冲印胶卷时使用。一、基本原理我们知道,摄影中有三个基本的参数,即胶卷感光度(ASA),快门值(T),光圈值(F)。一般这三个参数 A photometer is a photoelectric instrument used to measure the intensity of light in photography. It can scientifically measure the strength of the light, pointed out that the exposure aperture and shutter should have what kind of combination, in order to make the film get the best exposure. The traditional light meter are mechanical, they often can not take into account the backlight and flash measurements, incomplete, and the reading is not intuitive, this paper aims to introduce a single-chip 80C31 digital photometer controlled. Its characteristic is not only to measure the intensity of the background light, but also to measure the light intensity when the flash as a light source, and liquid crystal display of values ​​and symbols, but also as a timer for darkroom printing film used. First, the basic principles We know that there are three basic parameters of photography, film sensitivity (ASA), shutter speed (T), aperture value (F). Generally these three parameters