# DNG as raw file format questions



## Replytoken (Jan 22, 2014)

Until this month, all of the digital cameras that I have shot with have used their own raw format (NEF, ORF, RW2).  However, I recently acquired a Ricoh GR, and its native raw format is DNG.  As I normally convert my raw files to DNG using Adobe's Raw Converter with ImageIngester Pro 3, I have a few questions about the GR files.  First, is there any difference between Ricoh's DNG files and those that have been converted by the Adobe Converter?  And, what happens if I run the Ricoh GR file through the Adobe converter?  I do realize that I can run some test files, but that is probably not going to directly tell me much about the file's structure or any possible changes, so I thought I would pose the question to those who like have delved into the DNG file structure.  Any information would be greatly appreciated.

Thanks,

--Ken

P.S.  While I am still getting my feet wet with the GR, it packs a lot of IQ into a pretty tiny package.  Very impressive.


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## Tony Jay (Jan 22, 2014)

The technical specs should tell you what version of DNG the Ricoh GR generates.
Compare it with the version the ARC produces and that should tell you something.
If they are slightly different versions either the Adobe site or even Wikipedia will provide information as to the technical differences.
The important thing is that the Ricoh DNG will still recognized by any application that supports DNG.
I don't think that putting that DNG format through ARC is either desirable or necessary.

I am at work right now and not in a osition to research  this stuff in detail.

Tony Jay


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## Bryan Conner (Jan 22, 2014)

Another thing to consider is that once you run your camera's dng file throught the Adobe dng converter some raw converters will no longer recognize the file as being a raw file from a camera.  DXO 9 (and maybe earlier versions) is one such converter.  It will read your dng files that come directly from your Ricoh GR, but will not read files that are converted by Adobe Dng converter/Lightroom/ACR.  DXO does not consider the converted files to be proprietary camera raw files and believes that proprietary camera raw files are safer to process than converted ones.  I had an email discussion with a DXO rep about dng and this is what I was told.


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## Jim Wilde (Jan 22, 2014)

Ken, one other thing to investigate, as I known you are keen on image verification, is whether the SOOC DNG files contain the checksum that allows Lightroom to run it's DNG Validation. I doubt that it does.....


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## clee01l (Jan 22, 2014)

I used to own a Pentax. It created DNGs (Probably like those from your Ricoh) These are true RAW images in a DNG container. An LR/ACR Converted DNG (can be/is) a Linear DNG. I'm not sure which happens automatically, but ACR does more than copy the RAW data from a Proprietary RAW container to a DNG Container.  Your Ricoh DNG is a true RAW file in a DNG container.  The same as a NEF is a true RAW file in a NEF container.  CR2, NEF and DNG are all variants of the TIFF/EP6 standard.

You may find this link useful.  It is where I get most of my understanding about DNGs created in the camera and created by the DNG Converter. 
http://www.barrypearson.co.uk/articles/dng/linear.htm


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## Replytoken (Jan 22, 2014)

Too much good information to reply individually, so I am going to give everybody a big THANK YOU! for your suggestions and information.  I was reading that Adobe DNG Converter 8.1 supported the Ricoh GR, and that had me wondering, but I believe that what Cletus has posted explains that.  I will probably run the files through the converter, but save the originals as well, just as I do with my other camera files.  If I take this route, I do not believe that it will create an issue for file validation, but will try to check when I get the chance.  As always, very helpful information from everybody.  I truly wish other forums were as useful and pleasant as here.

Thanks,

--Ken


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## Den (Jan 22, 2014)

I'm not sure why you would run them through the DNG converter. They are already DNG.


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## Replytoken (Jan 22, 2014)

Den said:


> I'm not sure why you would run them through the DNG converter. They are already DNG.



Cletus' post above touches on the differences between the DNG files.  If I understand correctly, and if what he describes is correct, and I have no reason to date not believe so, then there is a difference between a DNG file containing a raw image, and a DNG file containing a file that has been converted to linear DNG by Adobe's converter.  So, in short, they should both work in LR, but what they contain is not exactly the same.  For a variety of DAM reasons, I believe that I would like to have both versions backed up (see Bryan's and Jim's posts), and the converted one imported into LR.

--Ken


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## Jim Wilde (Jan 22, 2014)

I don't believe a DNG file created by LR from a proprietary Raw file is linear, i.e. it will still be the original mosaic data in a DNG container (plus the DNG hash, and/or Fast Load data, and choice of embedded preview size). There's an *option *in the stand-alone converter to produce linear DNG, though not sure why anyone would want to do that.


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## Roelof Moorlag (Jan 22, 2014)

Another good source is dpbestflow: http://www.dpbestflow.org/DNG


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## Replytoken (Jan 22, 2014)

Jim Wilde said:


> I don't believe a DNG file created by LR from a proprietary Raw file is linear, i.e. it will still be the original mosaic data in a DNG container (plus the DNG hash, and/or Fast Load data, and choice of embedded preview size). There's an *option *in the stand-alone converter to produce linear DNG, though not sure why anyone would want to do that.



It appears that I am going to need to learn a bit more about DNG file structures to better understand the differences.  Lots of reading ahead!

--Ken


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## Replytoken (Jan 22, 2014)

Roelof Moorlag said:


> Another good source is dpbestflow: http://www.dpbestflow.org/DNG



Thanks for the reference.  Isn't this Peter Krogh's work?  I started my pre-LR journey at the DAM forum back in 2007.  Looks like I need a refresher course on DNG files.

--Ken


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## Den (Jan 23, 2014)

Geez. After reading all the information in the articles cited by Cletus and Roelof, my head is spinning. I will continue to shoot in RAW (DNG) as Pentax K-5 can, not do any conversion and not worry about it.:hm:


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## clee01l (Jan 23, 2014)

Den said:


> Geez. After reading all the information in the articles cited by Cletus and Roelof, my head is spinning. I will continue to shoot in RAW (DNG) as Pentax K-5 can, not do any conversion and not worry about it.:hm:


That was my solution with the K20D.  I see no compelling reason for me to convert to DNG, However if the camera will do that in situ, all the better for the camera.


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## Replytoken (Jan 23, 2014)

Den said:


> Geez. After reading all the information in the articles cited by Cletus and Roelof, my head is spinning. I will continue to shoot in RAW (DNG) as Pentax K-5 can, not do any conversion and not worry about it.:hm:



Yes, it is going to be a head-spinning read when I find the time.  But, thankfully, none of it is time or workflow critical.  Unless somebody has some information that indicates there is an issue or problem with running a raw DNG through the converter, I am going to approach it for now as a personal choice.

--Ken


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## Roelof Moorlag (Jan 24, 2014)

> Unless somebody has some information that indicates there is an issue or problem with running a raw DNG through the converter, I am going to approach it for now as a personal choice.


On the contrary, the advantage of running your DNG's through the DNG converter is that their integrity is checked (again). The converter will create a log of all files that can not be opened of parsed properly!

Roelof


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## Roelof Moorlag (Jan 24, 2014)

> Thanks for the reference. Isn't this Peter Krogh's work? I started my pre-LR journey at the DAM forum back in 2007. Looks like I need a refresher course on DNG files.


Yes Ken, Peter Krogh is one of the two main sources of dpbestflow.org It's very valuable, a lot of information from his book(s) can be found there. However, reading the book is more comfortable and it's more 'storytelling'. I can recommend it to everyone.


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## Replytoken (Nov 3, 2014)

I hate to revive an old thread, but I have a quick, and hopefully easy, question.  Is there any way inside or outside of LR to determine if a DNG file that I have imported into LR is the native DNG, or if it has been converted by either LR or the stand-alone DNG converter?  I am assuming that there is some metadata residing somewhere, but I am not sure what or where I should be looking.  any help would be greatly appreciated.

Thanks,

--Ken


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## johnbeardy (Nov 3, 2014)

It depends which program you're using, but I think the EXIF Software field would reveal it.


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## Replytoken (Nov 3, 2014)

johnbeardy said:


> It depends which program you're using, but I think the EXIF Software field would reveal it.



Thanks, John.  I'll have a look in detail the next time I open LR.

--Ken


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## Replytoken (Nov 4, 2014)

johnbeardy said:


> It depends which program you're using, but I think the EXIF Software field would reveal it.



Yes, that is the place.  It is a field that I normally do not pay much attention to, but if the files has been converted by software, it will be noted.

Thanks,

--Ken


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## Replytoken (Nov 5, 2014)

johnbeardy said:


> It depends which program you're using, but I think the EXIF Software field would reveal it.



It is an EXIF field that I never paid much attention to, but if you convert a file, it will list the program that made the conversion.

Thanks,

--Ken


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