Targeting: Principles and Practice
暂无分享,去创建一个
In the flash photography exposure control system disclosed, an illuminating device produce flash light quantity P for a main portion and subordinate portion of an object to be photographed. A shutter device opens for a time T and closes on the basis of the light from the illumination means. Distance measuring means measure the distance Dm to the main portion of the object. A diaphragm arrangement cooperates with the shutter device and produces a diaphragm value F for adjusting the exposure amount. A brightness measuring device measures the brightness Bm of the main portion and the brightness Bb of the subordinate portion of the object. Operating means adjust at least two of the following parameters: flash light quantity P, the opening time T of the shutter device, and the diaphragm value F of the diaphragm device determined by the distance obtained by the distance measuring means and brightness obtained by the brightness measuring means. The operating means thus produces a proper exposure which takes into account the natural light and flash light supplied to the main and subordinate portions of the objects.
[1] Timothy Besley,et al. The principles of targeting , 1990 .
[2] M. Grosh. Administering Targeted Social Programs in Latin America: From Platitudes to Practice , 1994 .
[3] S. Carvalho,et al. Safety Net Programs and Poverty Reduction , 1997 .