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Author Topic: Convert to DNG or not to convert, that is the question  (Read 10131 times)

Steve House

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Convert to DNG or not to convert, that is the question
« on: February 19, 2011, 08:16:29 am »

Sounding a bit like one of my old metaphysics professor's exam questions, what are the arguments for and the arguments against converting to DNG on import into LR3? Shooting NEF camera raw on a Nikon D700 and occasionally CRW camera raw on a Canon P&S.  My present workflow has been to work in DNG, importing from the camera card into my working folders and converting to DNG in the process, while putting backup copies of the original raw files into a second set of archive folders on an external drive as well.  Any advantages or disadvantages to this approach versus keeping the working copy of the files in the original raw format or is it really just a toss of the coin?
« Last Edit: February 19, 2011, 08:23:21 am by Steve House »
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pegelli

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Re: Convert to DNG or not to convert, that is the question
« Reply #1 on: February 19, 2011, 08:23:04 am »

Toss of the coin as far as I'm concerned, as long as you keep and back-up your original files as they came of the camera.
Editing an original raw or a dng has no significant difference.
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pieter, aka pegelli

Edhopkins

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Re: Convert to DNG or not to convert, that is the question
« Reply #2 on: February 19, 2011, 08:46:19 am »

Is there any real risk in just dumping the original raw files and keeping only the DNG files as your "original"?

My sense is that if I have to keep two different kinds of raw files: the original, camera specific form and the standardized DNG form, I might as well not convert to DNG at all.

Isn't the conversion of camera specific raw format files to DNG files a conversion that by design preserves EVERYTHING in the original raw file?

If you convert to DNG, import into lightroom, look at the DNGs in lightroom--so you know you don't have major corruption in the conversion process--AND backed up the DGN files to at least one back up disk, isn't it reasonably safe to clean off your camera card and kiss the original raws good bye?

What am I missing here?

ed
Baltimore
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pegelli

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Re: Convert to DNG or not to convert, that is the question
« Reply #3 on: February 19, 2011, 09:09:50 am »


What am I missing here?


There have been reports that some camera info in non specific/standard exif fields doesn't get transferred.
For instance in the Sony files it strips the field that indicates which AF sensor was used for focus. Currently no raw converter (even not the sony one) makes it possible to read that field, so it's not a problem. However who knows what happens in the future.
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pieter, aka pegelli

ErikKaffehr

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Re: Convert to DNG or not to convert, that is the question
« Reply #4 on: February 19, 2011, 09:54:02 am »

Hi,

One good reason to keep original raw files is that there are plenty of raw-converters that don't support DNGs. I inquired Bibble Labs about their approach and they feel that DNG does not have all info needed. There is an option in DNG to preserve original info. That make DNG files fatter. In my view it's crazy to support hundreds of raw formats instead of one. So I hope DNG develops to a level where it would be acceptable to all, alternatively that a better open file format is developed.

Personally, I use DNG only and I'm quite happy.

Best regards
Erik
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deejjjaaaa

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Re: Convert to DNG or not to convert, that is the question
« Reply #5 on: February 19, 2011, 10:40:05 am »

Isn't the conversion of camera specific raw format files to DNG files a conversion that by design preserves EVERYTHING in the original raw file?
no, it is not - one more example - it turns out that Sigma .X3F raw files while being converted by Adobe's DNG converter have NR applied to the data (NR that not only can't be controlled or switched off by you - but it is of pre ACR6/LR3 quality)... http://forums.adobe.com/thread/791442?tstart=0
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deejjjaaaa

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Re: Convert to DNG or not to convert, that is the question
« Reply #6 on: February 19, 2011, 10:46:20 am »


One good reason to keep original raw files is that there are plenty of raw-converters that don't support DNGs.

Capture One from P1 is also the fine example of the converter which while supports opening native in camera DNG raw files (speaking about Pentax here) does not support them fully - some adjustments are not enabled for .DNG raws, but available for .PEF raw format... that is not taking into account that it renders native .DNG files incorrectly (magenta cast) for several recent generation of Pentax cameras, no support for DNG profiles, etc.
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john beardsworth

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Re: Convert to DNG or not to convert, that is the question
« Reply #7 on: February 19, 2011, 11:14:26 am »

In other words, those are defects of C1, not of DNG.
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JRSmit

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Re: Convert to DNG or not to convert, that is the question
« Reply #8 on: February 19, 2011, 11:42:11 am »

My view on this is that, as long as DNG (the raw part of it) is not the universally adopted Raw format used by all cameras, it is yet another raw format. Thus is converting to dng for that matter of no added value. Also for longer term archival it is not the universally adopted format. For the latter i believe tiff is the better choice. But then, that is not a camera raw format.
Wrt to raw camera images, As long as my camera-specific raw formats are supported it is no big deal. If some time in future that ceases to be the case, a conversion to a still supported format is one option, converting it to a rgb image like tiff another.
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deejjjaaaa

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Re: Convert to DNG or not to convert, that is the question
« Reply #9 on: February 19, 2011, 11:45:39 am »

In other words, those are defects of C1, not of DNG.

of course, format itself is not more defective than .bmp :)... however if C1 is your converter of choice (or Bibble or some others or most of OEM raw converters), DNG is simply not usable - whether it is native .DNG or converted .DNG (converted from .PEF by Adobe DNG converter or by OEM Pentax DCU utility or in the form of linear DNG from DxO or converted from .PEF to .DNG by C1 itself  ;D)... so as a part of a work-flow, as an intermediate format like .TIFF it is OK - but as a solution for archive storage ? no way... it does not matter that you want to blame the raw converters - it is just not as universal as some people want to think
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john beardsworth

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Re: Convert to DNG or not to convert, that is the question
« Reply #10 on: February 19, 2011, 12:13:45 pm »

Nothing is supported universally, is it? While support amongst minority raw converters isn't anywhere near as complete as one would hope, that's not the result of an inherent weakness of DNG or its concept - it's down to the vendors' mix of competence / commercial decisions.  And you can leverage DNGs in other apps that play important roles in the workflow such as cataloguing apps. On balance it's probably worth converting to DNG and just keeping your raws in an extra archive.
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deejjjaaaa

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Re: Convert to DNG or not to convert, that is the question
« Reply #11 on: February 19, 2011, 12:56:23 pm »

While support amongst minority raw converters isn't anywhere near as complete as one would hope, that's not the result of an inherent weakness of DNG or its concept - it's down to the vendors' mix of competence / commercial decisions.


it does not matter - from the practical standpoint .DNG has miniscule market share in cameras (Pentax /and even there .DNG is an option which only some people use - I don't for example/, Samsung, Ricoh, Leica, may be couple of others) = 5% or so of the market... the same is the marketshare within OEM raw converters which a lot of regular folks outside the few ever writing in forums like LuLA are actually using (so they are not as minority as you wish to think)...


 And you can leverage DNGs in other apps that play important roles in the workflow such as cataloguing apps.

normal cataloguing apps are as good w/ non .DNG raws as they are w/ .DNG raws - so you gain nothing...

On balance it's probably worth converting to DNG and just keeping your raws in an extra archive.

no it is not - it is worth to archive and use the raw files in the form that your camera's firmware created them (and that actually might be .DNG - but we are talking about native DNGs here - not converted) and use .DNG only if some intermediate steps of your workflow requires that - just like tiff files that you might use when passing the output of your raw converter to photoshop (typical example - DxO as a raw converter generating linear DNG file with DxO corrections baked in it to be processed further in LR/ACR-Photoshop)

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john beardsworth

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Re: Convert to DNG or not to convert, that is the question
« Reply #12 on: February 19, 2011, 12:58:33 pm »

The anonymous monomaniac....
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pegelli

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Re: Convert to DNG or not to convert, that is the question
« Reply #13 on: February 19, 2011, 01:40:47 pm »

In other words, those are defects of C1, not of DNG.

I think it's more an omission than a defects, but might be wrong.

A defect is when they wanted to implement the functionality but it doesn't work
An omission if they didn't want (or didn't bother to) implement the fuctionality

Anyway, the end result is the same  ;)

 
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pieter, aka pegelli

digitaldog

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Re: Convert to DNG or not to convert, that is the question
« Reply #14 on: February 19, 2011, 06:08:00 pm »

On balance it's probably worth converting to DNG and just keeping your raws in an extra archive.

Yup, no harm, only pluses.
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Alan Goldhammer

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Re: Convert to DNG or not to convert, that is the question
« Reply #15 on: February 19, 2011, 06:38:59 pm »

Yup, no harm, only pluses.
Andrew, I really would like to know the pluses.  I'm shooting Nikons and occasionally a Canon S 90.  I use LR as the primary and PS for softproofing and some clean up if necessary.  Since my NEFs are processed seamlessly and I archive my LR catalogue in two separate places besides my primary computer drive, why should I convert to DNGs particulary since its another step and there may be a question if some EXIF data is dropped (not that I have any plans to go back to Nikon software.  As I see it "most" everyone uses LR these days and the camera makers must be aware of this.  Why haven't they moved to the DNG format as Leica (and maybe a couple of others) have?  I find it all puzzling.

Alan
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deejjjaaaa

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Re: Convert to DNG or not to convert, that is the question
« Reply #16 on: February 19, 2011, 08:08:48 pm »

Why haven't they moved to the DNG format as Leica (and maybe a couple of others) have? 
why should they ? there is no gain... DNG is TIFF and other raw formats are TIFF... there is absolutely the same effort to code/debug/etc that in firmware... Pentax can write its raw files in either .PEF or .DNG format - your choice - however very few (if any at all) people base their decision to buy Pentax or not based on that fact... it is a nice feature, but the very last to be considered
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deejjjaaaa

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Re: Convert to DNG or not to convert, that is the question
« Reply #17 on: February 19, 2011, 08:11:11 pm »

I think it's more an omission than a defects, but might be wrong.
I'd say it is rather an intentional act on their side and Bibble developers were saying directly that they intentionally do not want to support converted DNGs
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john beardsworth

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Re: Convert to DNG or not to convert, that is the question
« Reply #18 on: February 20, 2011, 05:34:07 am »

Andrew, I really would like to know the pluses. 
There's an inherent long-term plus in the format being publicly documented, and also in the file having one or more updated JPEG previews that other opps can display or output. So for instance, I could abandon LR and I would be able to see the adjusted image in Aperture's preview mode, in browsers like PhotoMechanic, or in cataloguing apps like Expression Media. These apps can read and display the updated preview JPEG that's in the DNG, do so extremely quickly, and without needing knowledge of the Adobe/LR adjustment parameters  (one had a good laugh at the earlier comment about "normal cataloguing apps are as good w/ non .DNG raws as they are w/ .DNG raws"). How that benefits you will vary, but for example there are people who use Bridge or even LR for processing, but catalogue their work with programs like Expression or Portfolio - and they see the adjusted DNG, pretty handy if you've had to make major corrections.

Another set of benefits is that the metadata is embedded in a file rather than in a sidecar xmp file. Many more 3rd party apps read metadata that's in the file than read it from sidecars (which can easily go missing). And that's even more true of writing metadata. So for example I might want to tag images from a trip with GPS co-ordinates. Apps like HoudahGeo on Mac or Geosetter on Windows will write the GPS EXIF metadata back to the original so it's available in Lightroom or other apps. Alternatively, I might change pictures' captions or star ratings in Expression Media or PhotoMechanic, and again want that metadata attached to the file itself, and therefore into an TIFs I produce from it, or JPEGs I put on Flickr or other online service. What do you reckon is safer - writing that EXIF and IPTC to a publicly documented format or to a proprietary one?

So apart from the archival value (objections tend to be along the lines of "hey, we'll surely have time to fix the roof when we see the storm clouds"), the key pluses are embedded previews and safely-embedded metadata, and how you can then take advantage of them in diverse workflows.

John
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sniper

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Re: Convert to DNG or not to convert, that is the question
« Reply #19 on: February 20, 2011, 05:58:58 am »

One problem seems to that while .DNG should be a standard format in practice there are variations of it.   And there was/is talk of a .DNG 2 how thats going to fit in the mix is anybodies guess.

Personally I'm not convinced by the archival aurgument, I have plenty of computers with software that will convert my raw to whatever I need, they won't all become extinct overnight, it also occures to me that Tiff is probably a better archival firmat, even windows can open those.
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