“遮光”怎么读

“遮光”的英语可以翻译为：irising，dodging，diaphragmation，shading ...

为什么不给所有的镜头都配上遮光罩呢？Why aren't all lenses supplied with a lens hood?因此我们得制作一块很大的遮光窗帘。We therefore had to contrive a very large black-out curtain.那网球裁判戴着遮光帽檐.The tennis umpire wore an eye - shade....