主题：a RAW flaw？ -- 晨枫

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a RAW flaw？

这是Luminous Landscape网站上的一篇文章的标题，其实里面的flaw我在“数字单反优劣论”里面也提到过。

认真的数字单反使用者大多用RAW文件，而不是JPG文件。JPG文件小，什么计算机、什么软件都能读，但JPG相当于印好的照片，只能做有限的改动。所以用作“到此一游”的照片问题不大，但认真的摄影者不大用JPG作为源文件格式。

RAW是成像芯片上直接捕捉下来的信息，在将RAW转换成可视图像（如TIFF）的过程中，你可以调节线性、白平衡、曝光、色彩、饱和、亮度、对比、color space，所以相当于还没有冲洗的底片，你不但可以自己冲洗，而且可以每次按不同喜好反复冲洗，所以作为源文件更合适。

但RAW目前是一家一式，甚至一家多式，差不多每新出一种DC就是一种新的RAW格式，EOS 10D和20D就不一样。这也难怪，因为成像芯片的技术在飞速发展，所以相应的RAW也在变。据统计，现在RAW已经有100多种。

但问题有两个：

1、长期软件支持成问题，如果公司关门（Agfa刚关门）或终止软件支持，多少年后，你可能面对不能读自己的图像的问题。现在已经有读不出早期的RAW的问题了，而DC才有十年历史。

2、相机公司（如Nikon）开始对RAW加密，以保护自己的核心技术，毕竟RAW和成像芯片技术连得太紧了。而美国的新知识产权保护法律规定，擅自解密属于侵权。

这样，Adobe和Phase One这样的公司就不敢在自己的RAW converter里加RAW的解密，以避免“犯规”，Adobe已经公开拒绝将Nikon的D2x和D50加入Adobe Raw Converter。而摄影者就被夹在中间，必须用厂商软件转换RAW，然后export到图像编辑软件做进一步的加工，软件integration和使用上的方便全没有了。这样，我们又回到VHS和Beta大战的时代，只不过这次，参战的有100多个格式，而且还在迅速增加。

Nikon的DSLR用户已经开始强烈抗议，不知道Nikon会不会悔改。另一方面，有人在推动Open RAW。Adobe已经发布DNG的公开标准，Leica已经加盟。但Adobe需要Canon、Olympus、Nikon、Sony等加盟才有用。不考虑芯片发展的单纯软件格式也是没有生命力的。从IT发展历史来看，标准化的道路是对的，但也是漫长的，将迅速发展的硬件技术和软件绑在一起的标准更难。

看来在数字单反上“等等看”还是对的。

关键词(Tags): #摄影小札，

复 a RAW flaw？

家园

微软推出了一款RAW Image Thumbnailer and Viewer

喜欢操作RAW FILE的朋友这下有免费的工具了。点击这里下载RAW Image Thumbnailer and Viewer

After installing the Microsoft RAW Image Thumbnailer and Viewer Powertoy for Windows XP you will be able to view, organize, and print photos captured in RAW image formats from supported Canon and Nikon digital cameras.

This software offers the following benefits to digital photographers:

    * High image quality. This software uses the camera vendors' own processing libraries to provide the highest possible image fidelity for RAW images.
    * Superior color fidelity. Windows Image Color Management (ICM) is used to render images in the correct color space as determined by the photographer when the image was captured.
    * Familiar user experience. This software builds on the familiar Windows user experience and requires little or no learning curve.
    * Performance tuned for rapid previews. The software uses background processing and other techniques to ensure a good preview experience even for large images.

About RAW Images and Windows

Often likened to a ‘digital negative,’ a RAW image is the native image format for a growing number of quality digital cameras. RAW images typically contain the original camera sensor data recorded at the time of capture, along with camera settings and other information. Using special software, photogra-phers can “process” RAW images using a personal computer and can vary the exposure, white bal-ance, and other settings long after the image was captured. This creative flexibility and extra level of protection against mistakes are key reasons photographers choose to shoot RAW.

RAW images also preserve all of the quality capable of being rendered by the digital camera’s sensor. Capturing pictures in RAW avoids the inherent loss of color information and dynamic range that occurs when camera sensor data is processed to a compressed dynamic range format such as JPEG. For ex-ample, most current digital cameras are capable of capturing images with 12-bits of information per color channel. When processed to JPEG format, the image data is re-sampled to 8-bits per channel. As a result, some of the original information present in the image is lost, never to be recovered again. In addition, RAW images avoid any loss of fidelity due to image compression, as no “lossy” compression is used.

Today, RAW formats are not standardized across camera manufacturers. Each camera maker has its own RAW format (sometimes more than one). Additionally, the actual image data within the RAW file is specific to each camera model and sensor. As a consequence, only certain software programs can understand and process RAW images.

Some of the more common RAW image types in use today are:

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