



articles/Cameras/xpro1-page3
by Tom Lee Published 01/12/2012
File Formats
The X-Pro will produce a Raw file, various JPEG options or a combination of both. Here we ran into our first problem, we need to process Raw files to conduct our colour audits and calibrations of camera chips. Infuriatingly the Raw files will only open in Adobe Camera Raw 7.* and this has to be at least linked with Adobe CS6. This crippling flaw has also been extended to DNG processing, leaving us high and dry. It is now time for a rant! When the Raw format was first suggested, the graphics community wanted to retain an open standard so that anybody could open a Raw file, anywhere, anytime. Adobe have in many ways exploited the opportunity (as was predicted at the time) to leverage their product and effectively shut out anybody who either chooses, or does not have the resources, to upgrade their Adobe product. Claims that they cannot achieve agreement with camera makers fall on deaf ears about these parts - falling out occasionally with a camera maker might be a misunderstanding, serially falling out with almost all manufacturers and Apple Corp is starting to look like a personality defect; Adobe - remember The Ides of Quark, they treated their user base with distain and eventually paid a heavy price.
Testing Outdoors Overcast Sky JPEG format
We audited the accuracy of the camera by shooting a 24-patch Macbeth Chart in overcast daylight using 200ISO and auto white balance. The exposure accuracy was almost perfect, only needing a 1/10 point f-stop exposure and +5 points on white balance. The target was then audited using the Rags Gardner script which reported an overall error of 4.6 ?E00.
The worst colour was the red patch at 9.9 ?E00. The most accurate colours were the yellows.
Outdoor Testing Raw and JPEG files
Jon Ashton kindly processed a .RAF Raw file for us using the same parameters for the Macbeth chart. It was noticeably better, with the overall error falling to 3.6 ?E00 and the worst colour was switched to the yellow green at 6.1 ?E00. Overall the use of ACR has tightened the error spread across all the colours as confirmed by the halving of the standard deviation of the statistics (SD is a measure of the spread of error in a set of figures).
In the composite image the Raw file is on the bottom. The increase in red saturation is obvious, other differences are difficult to pin down. The histograms of the errors are slightly more revealing when they are carefully studied.
Mike's Rant About Raw File Compatibility
This was lifted from the Adobe website:
"The public archival format for digital camera raw data Raw file formats are extremely popular in digital photography workflows because they offer creative professionals greater creative control. However, cameras can use many different raw formats - the specifications for which are not publicly available - which means that not every raw file can be read by a variety of software applications. As a result, the use of these proprietary raw files as a long-term archival solution carries risk, and sharing these files across complex workflows is even more challenging.
The solution to this is Digital Negative (DNG), a publicly available archival format for the raw files generated by digital cameras. By addressing the lack of an open standard for the raw files created by individual camera models, DNG helps ensure that photographers will be able to access their files in the future.
In addition to the Digital Negative Specification, Adobe provides the free Adobe DNG Converter (Windows | Mac OS), which easily translates Raw files from many of today's popular cameras.
Software developers and manufacturers can download the complete DNG Specification (PDF, 486k). DNG is supported by Photoshop from Photoshop CS to CS6, Photoshop Elements 3 to Photoshop Elements 10 and all versions of Photoshop Lightroom."
Fine words butter no parsnips indeed!
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