The DAM Forum
Welcome, Guest. Please login or register.
October 24, 2014, 01:29:54 PM

Login with username, password and session length
Search:     Advanced search
28019 Posts in 5139 Topics by 2910 Members
Latest Member: kbroch
* Home Help Search Login Register
+  The DAM Forum
|-+  DAM Stuff
| |-+  DNG
| | |-+  Why DNG
« previous next »
Pages: [1] 2 Print
Author Topic: Why DNG  (Read 12724 times)
JoeThePhotographer
Full Member
***
Posts: 208


View Profile
« on: February 06, 2009, 09:26:42 AM »

I never wanted to bother with DNG because I wanted to preserve the ability to convert RAW files with Nikon's software.  But since I am now happy with the latest version of Adobe Camera Raw's ability to convert Nikon RAW files, DNGs are not necessarily out of the question. 

Only thing is, I don't recall the main (or any convincing) advantages of DNG.  Can anyone help?

Joe.
Logged
ScottBuckel
Full Member
***
Posts: 245


View Profile Email
« Reply #1 on: February 06, 2009, 09:56:59 AM »

Joe -

There are a list of reasons that have been posted in threads in the past.  For me, I spent a lot of time on the fence about converting over to DNG, what convinved me was that DNG's are significantly smaller than NEFs.

SCott
Logged

Scott Buckel
Monrovia, CA
johnbeardy
Administrator
Hero Member
*****
Posts: 1813


View Profile WWW
« Reply #2 on: February 06, 2009, 10:12:38 AM »

Obviously you've got to appreciate the benefits, as Scott says, but what finally made me switch was trying it in practice. When CS2 came out, I gave a DNG workflow a go for a month, long enough to see if it was practical for me, but not so long that backtracking would be painful. I keep my NEFs as another backup format.

John
Logged
peterkrogh
Administrator
Hero Member
*****
Posts: 5682


View Profile Email
« Reply #3 on: February 06, 2009, 11:58:43 AM »

Joe,
The two most compelling reasons for me:
1. The DNG can contain a rendering showing the image as I want it to be seen, regardless of what program I look at it with (well, as long as the program can see the embedded preview).
2. The data validation hash can let you validate an entire archive with certainty.
Peter
Logged
JoeThePhotographer
Full Member
***
Posts: 208


View Profile
« Reply #4 on: February 07, 2009, 07:36:25 AM »

Peter,

I exported a couple of DNG's and Vista does not preview them in Explorer.  Doesn't Vista support DNG?

Joe
Logged
peterkrogh
Administrator
Hero Member
*****
Posts: 5682


View Profile Email
« Reply #5 on: February 07, 2009, 07:50:59 AM »

Joe,
There's a CODEC to do that.

http://labs.adobe.com/wiki/index.php/DNG_Codec

Neither Apple, nor Microsoft give you the option to view the embedded preview, - they parse from the raw data.

It's not surprising to me that the OS behavior is lagging, with regard to proper implementation of parametric imaging tools. Ideally, both OSs would offer the user the ability to view either raw data, parsed in some manner, or embedded previews, which would provide a predictable rendering.

Peter
Logged
danaltick
Hero Member
*****
Posts: 1616

evaa-xdtb@spamex.com danaltick
View Profile WWW Email
« Reply #6 on: February 12, 2009, 09:27:44 PM »

Peter,

You cite two compelling reasons.  I also like the fact that it is a single job jacket (no sidecars) with an open interface that continues to improve.  And of course, it's nice to know that our old DNG's can still be edited with today's Raw editors that support DNG.

Dan
Logged

WindowsXP, ImageIngester Pro, RapidFixer, IVMP 3, ACR4, Photoshop CS4, Controlled Keyword Catalog, Canon EOS50D
Bruce Van Inwegen
Newbie
*
Posts: 37


View Profile Email
« Reply #7 on: August 21, 2009, 06:23:29 AM »

Joe -

There are a list of reasons that have been posted in threads in the past.  For me, I spent a lot of time on the fence about converting over to DNG, what convinved me was that DNG's are significantly smaller than NEFs.

SCott

I adopted DNG as soon as it came out and due to paranoia, I've always embedded a copy of the original CR2 file in the DNG.  Recently I've been playing with the idea of dropping that policy.  A couple of tests confirm that my converted DNG files can be up to about 20% SMALLER than the origial RAW file.  What is happening to the data to reduce the file size?   Is this some sort of lossless compression?
Logged
johnbeardy
Administrator
Hero Member
*****
Posts: 1813


View Profile WWW
« Reply #8 on: August 21, 2009, 06:29:35 AM »

Yes, it's lossless. Just Adobe compression is sometimes tighter than the in-camera ratio which is also geared to clearing the buffer

I simply archive the NEFs separately. I have them already, so I may as well treat them as an extra backup format. Their filenames and folders match the corresponding DNGs .

John
Logged
danaltick
Hero Member
*****
Posts: 1616

evaa-xdtb@spamex.com danaltick
View Profile WWW Email
« Reply #9 on: August 21, 2009, 06:38:39 AM »

Bruce,

It is a lossless compression so no loss in quality.  I've noticed that my DNG's are roughly the same size as my original raws once I embed the full resolution preview, so basically with the compression, I'm getting the preview for free.  Not a bad trade-off.  Neither Peter nor I embed the original raws.  I personally can't justify the overhead of hanging on to a proprietary format and keeping it backed up; especially in my DNG's where it would impact the speed of my workflow.  However, I assume no responsibility for anyone's loss of data as a result of taking my advice ;-).

Dan
Logged

WindowsXP, ImageIngester Pro, RapidFixer, IVMP 3, ACR4, Photoshop CS4, Controlled Keyword Catalog, Canon EOS50D
johnbeardy
Administrator
Hero Member
*****
Posts: 1813


View Profile WWW
« Reply #10 on: August 21, 2009, 06:52:19 AM »

The saving in file size varies very much with camera. IIRC it was about 25% with my D200 but minimal with the D700. In any case, I think it best to see the saving in file size as a happy by-product, not in itseld a reason to go with the format.

John
Logged
danaltick
Hero Member
*****
Posts: 1616

evaa-xdtb@spamex.com danaltick
View Profile WWW Email
« Reply #11 on: August 21, 2009, 07:28:04 AM »

John,

Very true.  There are quite a few other reasons to go with DNG that take higher precedence: full-res preview, validation hash, no sidecars, embedded profiles, open interface, backwards compatibility, etc.

Dan
Logged

WindowsXP, ImageIngester Pro, RapidFixer, IVMP 3, ACR4, Photoshop CS4, Controlled Keyword Catalog, Canon EOS50D
Paul Gulliver
Newbie
*
Posts: 2


View Profile Email
« Reply #12 on: September 20, 2009, 10:56:36 AM »

This is my first post to these forums so forgive me if I ask what may to others seem a silly question. I use ACDSee pro to process, catalogue and convert my raw images to jpeg. At the moment I archive my raw images but I am now wondering if software will be able to read these files in a few years time. With all the new raw formats coming into being is it likely that software developers will drop support for the older formats.
The problem I see now is if I convert my processed raw files to dng will I loose the processing - I'm guessing that I will. I assume that most people convert to dng first then process - are there any disatvantages to this - like slower processing.

Paul
Logged
peterkrogh
Administrator
Hero Member
*****
Posts: 5682


View Profile Email
« Reply #13 on: September 20, 2009, 02:27:03 PM »

Paul,
First, it's unlikely that your files are going to be unreadable in a few years, particularly if you use a major brand camera.  They are likely to be readable for at least a decade, and maybe several decades. Open source rendering tools like DCraw make inaccessibility unlikely in the near term.

But, as you point out, the work you do to files, which represents a lot of value, is not as assured.  There are a lot of things that could happen:

ACDSee could go under and stop development.
They could drop the rendering part of the software in the future.
They could change the algorithms so that previously adjusted files render differently (Most Parametric Image Editors have done this to some degree in the past).
You might change the software you use, and no longer want to maintain a copy of the program.

All of the above are problems with just-in-time rendering. If you use a program for this, you are making a bet that they won't leave you in the cold in the future.

DNG provides a reasonable safety net, since the rendering can be bundled up with the raw data and is not dependent on owning the program (at least to get access to an 8 bit version of the finished file.  The choice for a program to support DNG is a resource allocation one, since there is no licensing cost involved. If customers don't ask, then they will likely allocate resources elsewhere. If customers demand, then they have a tougher choice.

It's also likely that at some point in the future someone will make a tool to insert your ACDSee JPEGs into an Adobe-created DNG. The DNG spec provides for the embedding of additional renderings - so the engineering to do this is actually not complex at all.

I can't make the choice for you, but I can tell you the options...
Peter



Logged
danaltick
Hero Member
*****
Posts: 1616

evaa-xdtb@spamex.com danaltick
View Profile WWW Email
« Reply #14 on: September 20, 2009, 03:11:09 PM »

Paul,

From Peter's explanation, I would assume that the Adobe DNG converter would not interpret your ACDSee metadata instructions.  You would need an ACDSee DNG converter to do that.  Each Raw editor needs its own converter.  Both Lightroom and Adobe Camera Raw generate the same metadata instructions from raw files; therefore, they can share the same converter.

Dan
Logged

WindowsXP, ImageIngester Pro, RapidFixer, IVMP 3, ACR4, Photoshop CS4, Controlled Keyword Catalog, Canon EOS50D
Pages: [1] 2 Print 
« previous next »
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!