DNG - The non standard standard

Lowell Goudge · 07-20-2009, 10:13 AM

Note the response below from Corel, regarding the inability of PSPX2 to properly import DNG files from my K7

"Thank you very much for your e-mail.

If the DNG file came from Adobe RAW converted, then it is supported and should be opened. If the DNG file came directly from the camera, it is currently not a supported format.

Please do not hesitate to contact us for any further questions."

what good is a standard if it is not fully supported and implemented.?

To use either PEF or DNG files from my K7 in PSPX2 I have to run Adobe's DNG Converter first. PEF Files I can understand, but DNG? And why can my very old EXIF editor read DNG files from my K7 yet PSP can't?

stevebrot · 07-20-2009, 10:26 AM

I remember reading about this many months ago shortly after I got Lightroom 1.x and my K10D. Apparently the DNG from a Pentax camera contains certain extensions that are not strictly compliant with the Adobe standard. This would not be an Adobe problem per se beyond indicating one or more weaknesses in the standard. In any case, the DNG compatibility problem is one reason why I use PEF.

Steve

Lowell Goudge · 07-20-2009, 10:37 AM

Originally Posted by stevebrot

I remember reading about this many months ago shortly after I got Lightroom 1.x and my K10D. Apparently the DNG from a Pentax camera contains certain extensions that are not strictly compliant with the Adobe standard. This would not be an Adobe problem per se beyond indicating one or more weaknesses in the standard. In any case, the DNG compatibility problem is one reason why I use PEF.

Steve

When I put this question to pentax they responded

"Thank you for contacting Pentax regarding you're K-7.
The DNG format is designed to work in versions of Adobe Photoshop. It might be a newer version of DNG from Adobe on the K-7. You might want to try updating you're program or using our program, Photo Lab and Photo Browser (or Adobe).
"

So who's right?

simico · 07-20-2009, 11:17 AM

I also noticed that if a software can't open my K-m's PEF files then it also can't open my cam's DNG files either. However the same software can open DNG created by PPL. Looks like Pentax's DNG is somehow different

Lowell Goudge · 07-20-2009, 11:57 AM

simco

if this were the case, then why does my 2 year old version of KUSO Exif Viewer open them perfectly?

in fact it also opens my PEF files from the K7.

It would seem that the PSP is explicitly and unnecessairly excluding camera types it does not identify.

WheresWaldo · 07-20-2009, 12:14 PM

Originally Posted by Lowell Goudge

...
It would seem that the PSP is explicitly and unnecessairly excluding camera types it does not identify.

Most definitely. Usually older software sometimes will ignore extra info in the exif and only tell you about what it knows. In general applications like PSP, PS, LR, etc., specifically look for camera id's it knows before processing those files rather than some generic interpretation of the DNG output.

Lowell Goudge · 07-20-2009, 12:44 PM

waldo

its too bad, because this defeates the purpose of the standard,

The idea of a standard is that it should easier to use files everywhere, but this implementation makes it absolutely no better than camera raw in PEF format.

junyo · 07-20-2009, 12:52 PM

Originally Posted by Lowell Goudge

simco
It would seem that the PSP is explicitly and unnecessairly excluding camera types it does not identify.

...or PSP is detecting chunks of the file that it's not sure of (non-standard hooks or extensions to the format)and rather than a) ignore or b)risk misinterpeting that data, they're opting to just not take the chance. Which, from a dealing with critical data standpoint, is less than optimal, but better than normal. I don't know that to be the case but it's equally plausible.

*Wheatfield* · 07-20-2009, 12:56 PM

My Photoshop 7 (pre CS, not elements) file browser and raw converter can decode my K-7 DNG files.
I'm kind of leaning towards Corel not being quite up front with regards to DNG.

Lowell Goudge · 07-20-2009, 01:48 PM

what is absolutely amazing is that PSP X works just fine with the DNG files from the K7.

PSP X1 displays the thumbnail as black, and the opened image is black, and PSP X2 displays the thumbnail as black but can;t open them, and PSP X2 ultimate displays thumbnails as black but can open the files.

so much for progress and standards.

stevebrot · 07-20-2009, 02:01 PM

Originally Posted by junyo

...or PSP is detecting chunks of the file that it's not sure of (non-standard hooks or extensions to the format)and rather than a) ignore or b)risk misinterpeting that data, they're opting to just not take the chance. Which, from a dealing with critical data standpoint, is less than optimal, but better than normal. I don't know that to be the case but it's equally plausible.

Thanks for the more complete explanation. To elaborate a little further...It is apparent that Adobe uses a more "relaxed" parser and disregards anything that does not make sense with the intent of "cleaning up" later. PSP, on the other hand, appears to be using a strict parser that "insists" on full compliance with the DNG standard.

This sort of thing happens all the time in software development. It seems that the guys/gals at Corel just are a little more anal about the standard than Adobe.

Steve

BTW...It is both easier and cheaper from a software development perspective to simply "barf" when an error state (non-compliant file) is detected. Failing gracefully with maximum data preservation is a much more difficult task.

Edvinas · 07-20-2009, 07:01 PM

Originally Posted by Lowell Goudge

So who's right?

Well, both answers from Corel and Pentax are quite lame.

simico · 07-21-2009, 04:04 AM

Originally Posted by WheresWaldo

In general applications like PSP, PS, LR, etc., specifically look for camera id's it knows before processing those files rather than some generic interpretation of the DNG output.

Exactly! For example Bibble checks the manufacturer and camera model in the EXIF and if it doesn't find exactly the same texts in its own internal manufacturer/camera database then it refuses to open the file. After Hoya bought Pentax and the manufacturer text was modified in new production cameras, Bibble refused to open raw files of those cameras simply because the manufacturer text was different.

photog · 07-21-2009, 06:02 AM

You might like to take note that Lightroom 2.4 was released before the K7 was released to retail. LR2.4 fully supported the K7 even before its release.
LR now in v.2.4 is the most versatile image editing software and the best supported.
It can edit tif, jpg dng in all of its iterations as well as ALL of the dslr raw formats.