<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[jeff_5388的专栏]]></title><description><![CDATA[]]></description><link>https://blog.csdn.net/jeff_5388</link><language>zh-cn</language><generator>https://blog.csdn.net/</generator><copyright><![CDATA[Copyright &copy; jeff_5388]]></copyright><item><title><![CDATA[光圈优先的应用]]></title><link>https://blog.csdn.net/jeff_5388/article/details/4732721</link><guid>https://blog.csdn.net/jeff_5388/article/details/4732721</guid><author>jeff_5388</author><pubDate>Tue, 27 Oct 2009 11:32:00 +0800</pubDate><description><![CDATA[光圈的概念：光圈（Aperture）在相机镜头中由几片极薄的金属片组成，中间能通过光线。通过改变孔径的大小来控制进入镜头的光线量。光圈开得越大，通过镜头进入的光量也就越多。光圈通常用F表示：            镜头的焦距F =   －－－－－－－－        镜头口径的直径、  F值越小，则光圈越大。F值越大，则光圈越小。 光圈除了控制曝光，最重要的是景]]></description><category></category></item></channel></rss>