回顾:尼康D800数码单反，第2部分:可用性和图像质量

毫无疑问，具有视频功能的数码单反相机呈现出与专业消费摄像机截然不同的画面, for about the same price. 此外，你还可以获得杀手级的静止画面，这是任何摄像机都无法比拟的，即使是5K RED epic也不行. 当相机是36mp，全画幅，尼康D800时尤其如此. 

我从尼康收到的D800和尼克尔24-120mm VR镜头系统，售价4200美元. A decent prosumer camcorder, like the Panasonic AG-AC160, which I had an opportunity to test a few months ago, has a street price just north of $4,000. So they are definitely comparable in price. 真正的问题是图像的外观，以及可用性和功能.

In Part 1 of this two-part series on the D800，我研究了D800作为摄像机的操作和功能. Now, in Part 2, I'll share some usability notes, 我们将D800的音频和视频测试结果与另一款备受推崇的单反相机进行了比较, the Panasonic GH2, and to a more traditional prosumer camcorder (Figure 1, below).

Figure 1. 更小的相机(从左到右):消费摄像机，尼康D800，松下GH2.

Ergonomics

dslr的很大一部分用于独立电影制作. There, you take time to set up for a shot. You shoot the shot. You stop. You make adjustments. You repeat the whole process again. And again. And again. A camera where everything is completely manual, and where it takes time to nail your focus, adjust your audio levels precisely each time, is perfectly fine.

这些相机的另一个相当大的部分是用于你需要“在飞行中”记录长镜头的情况,” or shoot various events and situations as they happen, 你不能强迫在场的每个人都停下来，这样你就可以集中注意力了. You have to make these adjustments while you shoot.

我尝试用D800和附带的镜头录制一些实景视频. 即使在f/11的情况下，我试图让拍摄对象保持对焦，但经常受到以下四个因素的阻碍:

1. 静止相机镜头在非常接近和无限远之间的旋转距离非常短. On my beautiful loaner Nikkor 24-120mm VR lens, 它需要四分之一旋转的焦点环从接近2英尺到无限远. 实际上，我需要拍摄的大部分东西都在5英尺或更远的地方. 从5英尺到无穷远的旋转量是我拇指的宽度. 考虑到你的景深可能只有几英寸, 试着让这几英寸与我的拍摄对象到相机的精确距离相匹配，而他们, and I, are moving, is close to impossible.
2. The D800 does not offer autofocus while shooting video. 目前唯一具有这种功能的数码单反相机(带反光镜)是佳能T4i. 我的对比相机是无反光镜的松下GH2，它可以在录制视频时自动对焦. Any camcorder can do this. While many professional shooters prefer to focus manually, not having autofocus available at all presents a new, and possibly substantial, challenge.
3. The D800 offers no focus assist while recording. 没有办法在图像上打卡，没有峰值，没有距离刻度. 因此，如果你打算使用带放大镜的摄像机监视器，请事先了解摄像机的局限性. 有一些外接HDMI显示器允许你输入1:1的像素大小，使关键对焦更容易, and you can do this while recording video in the camera.
4. Lastly, 在录制视频时，按下快门按钮的一半，确实会迫使相机重新对焦——但是以一种“静态相机”的方式. 它将焦点向后滚动，然后向前，然后向后，然后聚焦. There's nothing subtle about it. 如果你在一个镜头中间尝试它，你可能会想要编辑掉这部分. But if you need focus fast and don't know which way to go, what I have come to call “Autofocus Assist” (see video below) can get you there in a pinch.