Ad
Ad
Ad
Pages: « 1 [2]   Bottom of Page
Print
Author Topic: Nat Coalson's DNG Chat with Eric Chan  (Read 6759 times)
Mark D Segal
Contributor
Sr. Member
*
Offline Offline

Posts: 6973


WWW
« Reply #20 on: December 01, 2011, 01:58:08 PM »
ReplyReply

Yes.
What happens a few generations down when you decide to refresh your image with another converter that does not support converted DNGs?
RAW converters get better over the years. Only the original RAW file has all the information. A normalized DNG does not.

cheers
afx

Andreas - what makes you think the best raw converters going forward will not support a widely-used format such as DNG? And why do you think there is a risk that these converters won't have all the information needed from the DNGs to do excellent conversions? It's fine to say there may be risks of this or that, but it doesn't mean much without being able to substantiate such risks in terms of their reasonableness or probabilities of occurrence.
Logged

Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Alan Goldhammer
Sr. Member
****
Offline Offline

Posts: 1674


WWW
« Reply #21 on: December 01, 2011, 02:33:33 PM »
ReplyReply

Andreas - what makes you think the best raw converters going forward will not support a widely-used format such as DNG? And why do you think there is a risk that these converters won't have all the information needed from the DNGs to do excellent conversions? It's fine to say there may be risks of this or that, but it doesn't mean much without being able to substantiate such risks in terms of their reasonableness or probabilities of occurrence.
Nikon NEF files are converted slightly differently using Nikon software vs Adobe.  I'm not saying that one is better than the other because I really haven't tested this (and probably don't really know what to look for in any event).  If I convert and toss out my NEF files, I forever give up on the use of Nikon software to do conversions.

 I guess I would also pose the question differently.  Adobe made DNG an open format but I think (don't know for sure) that Leica is the only camera that saves images in DNG.  The more critical question is why don't more camera mfrs support DNG?
Logged

digitaldog
Sr. Member
****
Offline Offline

Posts: 9188



WWW
« Reply #22 on: December 01, 2011, 02:50:08 PM »
ReplyReply

If I convert a raw file to DNG, what's missing?  What information is contained in the original raw that isn't carried over to the DNG?

My understanding is the proprietary data the 3rd party converter can't use anyway.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
RFPhotography
Guest
« Reply #23 on: December 01, 2011, 02:58:25 PM »
ReplyReply

Alan, that's true of any RAW converter.  DxO will process the same file differently from Adobe or C1.  Right?  The camera maker's own software will also process Raw files differently because it has access to the in camera settings that third party software doesn't make use of.  I think Hassy can also record in DNG. 

Andrew, that's what I would have thought.  In which case it doesn't really matter.  And Adobe (don't know about others) have the camera specific profiles available that are intended to mimic those other settings anyway.
Logged
Mark D Segal
Contributor
Sr. Member
*
Offline Offline

Posts: 6973


WWW
« Reply #24 on: December 01, 2011, 03:25:02 PM »
ReplyReply

Nikon NEF files are converted slightly differently using Nikon software vs Adobe.  I'm not saying that one is better than the other because I really haven't tested this (and probably don't really know what to look for in any event).  If I convert and toss out my NEF files, I forever give up on the use of Nikon software to do conversions.


You're not likely to be missing anything.
Logged

Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
afx
Jr. Member
**
Offline Offline

Posts: 89


WWW
« Reply #25 on: December 01, 2011, 03:30:36 PM »
ReplyReply

This runs in opposition to what Adobe (and others) have stated. 
Not really.  Read the transcript of what Eric said in the linked interview.

Quote
If I convert a raw file to DNG, what's missing?  What information is contained in the original raw that isn't carried over to the DNG?
Just like an MP3 can not be converted back to the WAV it was created from you can not create the NEF or CR2 from a DNG (unless you did a complete embed).
Converted DNGs do not contain dead pixels for example.

You might also have a look at how the DNG converter evolves which is a clear sign that the data is not identical, there is a really nice example in this article: http://www.libraw.org/articles/2-ways-to-nowhere.html

cheers
afx
Logged

RFPhotography
Guest
« Reply #26 on: December 01, 2011, 03:48:03 PM »
ReplyReply

Not really.  Read the transcript of what Eric said in the linked interview.

I did.  More than once.  For practical purposes, it contains the same data.  Not sure the calibration data from lower end cameras being cooked into the DNG is necessarily a bad thing.  Particularly if not all raw conversion software can read it.

Quote
Just like an MP3 can not be converted back to the WAV it was created from you can not create the NEF or CR2 from a DNG (unless you did a complete embed).

Yes, I know.  Not convinced it's a bad thing in this context.


Quote
Converted DNGs do not contain dead pixels for example.
What happens to them?

Quote
You might also have a look at how the DNG converter evolves which is a clear sign that the data is not identical, there is a really nice example in this article: http://www.libraw.org/articles/2-ways-to-nowhere.html

cheers
afx

I'll look at the article, perhaps on the weekend, when I have more time.
[/quote]
Logged
afx
Jr. Member
**
Offline Offline

Posts: 89


WWW
« Reply #27 on: December 01, 2011, 03:51:12 PM »
ReplyReply

Andreas - what makes you think the best raw converters going forward will not support a widely-used format such as DNG?
Check how many do so now?
And best is relative...

Quote
And why do you think there is a risk that these converters won't have all the information needed from the DNGs to do excellent conversions?
Again, excellent is subjective. It is no longer the original.

Just like I will not trash my CD collection by converting to MP3, I will not convert my images to DNG.

cheers
afx
Logged

Schewe
Sr. Member
****
Offline Offline

Posts: 5499


WWW
« Reply #28 on: December 01, 2011, 05:15:31 PM »
ReplyReply

My understanding is the proprietary data the 3rd party converter can't use anyway.

Actually for most raw file formats (such as CR2 and NEF) DNG will move most the proprietary metadata into the DNG safely...it just can't be used by ACR/LR. So that data isn't "gone" it's just stored. The camera maker's software COULD be written to read DNG.

Capture One can read DNGs–it can't use the processing engine in ACR/LR but it can use it's own engine for adjusting the DNGs. However, as far as I know, it can only read DNGs from cameras it already supports, so it's not a full DNG SDK implementation.

Personally, I don't toss my original raw files. For use in Lightroom it's useful to keep the original raws and use .xmp sidecar files since that's a much smaller backup. However, if I send raw files to anybody for any purpose, I only send DNG files so I can embed not only the settings but also IPTC metadata into the DNG file. In that case, DNG makes for a much better interchange format. And, DNG is still relatively new (released in 2004) and has gone through 3 major revs (now at DNG v1.3). I would expect that there are a lot more things Thomas Knoll wants to put into DNG (well, ok, I know that for a fact but can't talk about it :~).

And Leica is not the only company to adopt DNG, here's a list from the wiki page for DNG:

Casio supports DNG in their Exilim PRO EX-F1 and Exilim EX-FH25.

Leica's Digital Modul R for the Leica R8 or Leica R9 and the Leica M8 or Leica M9 natively support the DNG format.

MegaVision E Series Monochrome back.

Panoscan MK-3 digital panoramic camera.

Pentax supports DNG in their K10D, K20D, K200D, K2000, K-7, K-x, K-r and K-5 DSLR cameras.

Ricoh supports DNG in the Ricoh Digital GR, considered a professional compact, and the Ricoh Caplio GX.

Ricoh GXR is the latest, new and solely system of mirrorless interchangeable lens camera unit use also DNG.[43]

Samsung supports DNG in their Pro815 "prosumer" camera and GX-10 and GX-20 DSLR cameras.

Sea&Sea DX‐1G underwater camera.

Seitz Roundshot D3 digital back, used in cameras such as the 6×17.

Silicon Imaging Silicon Imaging Digital Cinema SI-1920HDVR.

Sinar now uses DNG as the raw file standard for their eMotion series of digital backs.

Also note that Adobe has offered DNG to the ISO to be a part of the revised TIFF/EP standard (ISO 12234-2). That's a slow moving process though. TIFF/EP is what most all raw file formats currently are based on including Canon, Nikon, Sony, Panasonic, Olympus, Fuji.

Again, it's useful to talk about the technical issues of DNG separately from the political issues.
Logged
Guillermo Luijk
Sr. Member
****
Offline Offline

Posts: 1291



WWW
« Reply #29 on: December 02, 2011, 02:23:17 PM »
ReplyReply

Question to Eric Chan (in case he shows up in this thread): as far as I know, most native RAW formats don't inform about each sensor's precise saturation point, i.e. the RAW value (or value range) in which RAW clipped data is encoded. RAW developers should know this value and apply it in the RAW conversion, so RAW developers have an internal table with sat points for each camera.

I guess the DNG file needs to encode the saturation point as metadata so that the RAW developer uses it to process the RAW file. Does Adobe DNG Converter have a fixed sat value for every camera? what if this value is not correct/optimum? how is the value chosen?.

Just to illustrate the consequences of chosing a wrong saturation point, a parameter the user cannot change in RAW developers since it is internal to the software:

This Canon 40D image has been developed using a wrong saturation point (in this case the one DCRAW uses internally for that camera):




This is the result when repeating the RAW development with a correct saturation point:




This is a RAW development from a Canon 7D using a version of ACR not yet fine tuned for that camera; same problem, magenta cast in the RAW clipped areas:




The same problem arises when developing Fuji S3/S5 Pro RAW files using ACR.

Regards
« Last Edit: December 02, 2011, 02:26:56 PM by Guillermo Luijk » Logged

Pages: « 1 [2]   Top of Page
Print
Jump to:  

Ad
Ad
Ad