On a clear day, the sun is so bright that your camera's meter will tend to underexpose everything else in the frame.
如果天气晴朗，阳光是如此耀眼，这就会造成镜头内其它所有物体都曝光不足。
2
By positioning the subject near the light source and allowing some of the subject to underexpose, the photographer can let light touch only the most important part of the subject.