佳能这次的EOS 5D Mark IV新技术不多，这个全像素双核RAW文件（Dual Pixel RAW简称DPRAW）算是个令人感兴趣的新鲜内容，发布前就引起了很多猜测，根据这个DPRAW的名字，我也做了猜测，结果证明我的猜测基本是准确的。
随便看一下吧 ：
还有一种可能的用法，这个双像素RAW文件里如果是存储了所有的半像素，那么就含有足够的相位差信息，可以计算出画面里每个物体的距离。
照片里含有每个物体的距离信息，这个可以带来大量相关的后期功能。
比如说，DPP里可以提供一个插件，自动按焦平面的距离计算照片里其他物体的虚化，从而让小光圈也能后期处理得到大光圈的虚化效果。这个因为有准确的距离数据，效果要比现在那些后期软件好很多。
在佳能各个区域的官方网站中，欧洲官网一直是最注重技术细节的，相比之下，美国和其它区域往往集中在使用特点上，对底层技术细节语焉不详。佳能欧洲官网上对DPRAW进行了相对详细一点的介绍，原文连接：http://www·canon-europe·com/cameras/eos-5d-mark-iv/dual-pixel-raw/
这里根据这网页提供的信息，结合基本的传感器和光学原理，对几个主要问题进行一下分析。
原文引用如下：
What is Dual Pixel RAW?
Dual Pixel RAW is a Canon innovation utilising both photodiodes on the EOS 5D Mark IV’s 30.4 Megapixel Dual Pixel CMOS AF sensor.
How it works
The Dual Pixel sensor’s pixels have a dual photodiode construction. This sensor design means the sensor can receive an A and B signals from the subject and to detect any phase differences between the two signals, allowing them to attain focus as part of the Dual Pixel AF system. When capturing the image, the sensor obtains the picture info from the combined A and B image signals. This technology making both focusing and image shooting possible with the same sensor.
During Dual Pixel RAW shooting, a single RAW file saves two images into the file. One image consists of the A+B combined image data and the other only the A image data.. This means the Dual Pixel RAW files contains both the normal image and also any parallax information, which can be measured and subject distance information extrapolated. As Dual Pixel RAW images contain two images they are therefore double the file size of normal RAW images.
文章来源：5D4全像素双核RAW功能的技术分析（资料来源：佳能欧洲官网）
