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Image Processing and Workflow RAW, DNG , TIFF and JPG. From Capture to Ready for Publish/Display. All software and techniques used within an image workflow, (except extensive retouching and repair or DAM).

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Old January 30th, 2007, 07:05 AM
samdring samdring is offline
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Join Date: Jun 2006
Posts: 17
Default Writing to raw

Everywhere I look (although I am yet to spot it here) people are warned away from writing to raw. I do not use dng but demand that all exif, iptc etc is written to raw and subsequent versions so that I am totally independent of any database in any dam software and, indeed, upon any corruption can re-create such a dbase within minutes directly from ALL my images. I do not like sidecar files. I shoot 100% raw and regularly use a range of converters (RSP, Lightroom, Canon's DPP and Adobe etc) and have 'trialled' some others. All raw files are downloaded with annotations written to those raw files either through Downloader Pro or IdImagers Downloader. I have never encountered any problem caused by this approach.

Question please: Has anyone had a problem caused by writing to raw or is the well published warning somewhat OTT?
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Old January 30th, 2007, 08:55 AM
Cem_Usakligil Cem_Usakligil is offline
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Join Date: Jun 2006
Posts: 5,940

Very good question, Samdring. Don't I know you from incidentally?
Nevertheless, I too am looking for an answer to this one. I can't imagine why one would have any issues with RAW corruption if the format of a certain camera manufacturer is well known, such as my CR2 files for Canon. Go figure!


Kind Regards, Cem

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Old January 30th, 2007, 10:17 AM
StuartRae StuartRae is offline
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Location: Wiltshire, UK
Posts: 1,025

Hello Sam,

I don't think it matters at all if you write your own Exif to the RAW file. What does matter is if the existing Exif is changed.

The Exif can include data pertinent to the image - WB, exposure, f-stop, etc. to be used by software that can take advantage of it - usually only the manufacturer's own conversion software. Once this is changed, in effect the image is changed.

Third party converters don't in general honour this Exif, so for example it won't effect the conversion by RSP. You will however remember that in the early days of RSE, files which had passed through Nikon software crashed it because the file was 'non-standard'. Canon DPP also changes the RAW file, although AFAIK this never caused any problems.

I prefer to keep my RAW file as it came out of the camera, or at least make a backup of the virgin data.


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Old January 30th, 2007, 10:32 AM
Asher Kelman Asher Kelman is offline
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Join Date: Apr 2006
Posts: 34,580

So, Stuart, does conversion to DNG, as promoted by Peter Krogh and others, keep the original MFR's data or is something lost?

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