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08-09-2020, 09:26 AM - 1 Like   #16
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QuoteOriginally posted by Frater Quote
Better check it out. E.g. someone discovered a bug on the Pentax-generated DNG files, for the K20D, where the white balance was wrong, so this information was lost.
see PEF vs. DNG when shooting RAW?: Pentax SLR Talk Forum: Digital Photography Review
As noted above, there is no evidence to support the conclusion. In addition, RAW files don't have white balance applied until the DNG/PEF is processed at some time AFTER the data is written to file. A "hint" is included in the makernotes metadata indicating what the camera would have applied if shooting JPEG, but that is the extent of it.


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08-09-2020, 09:36 AM   #17
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Irrelevant. Read again:

QuoteOriginally posted by Frater Quote
Better check it out. E.g. someone discovered a bug on the Pentax-generated DNG files, for the K20D, where the white balance was wrong, so this information was lost.
The white balance information is an information generated by the camera. If this valuable information is destroyed or lost, then Adobe's software (their auto white balance method), or probably any other software's, is hardly a replacement.

White balance of a scene is judged and determined by the camera. It is a precious part of a camera maker's "color science".

I thought these are basics, known since the beginnings of RAW files in the DSLR world

The camera's white balance information is so important, that its importance has been even misused. I remember that Nikon tried to encrypt this information in their RAW file for an early entry level DSLR, probably to promote the use of their proprietary Nikon software. They quickly gave up on that for the successor models, due to the community shitstorm upon them. This shows, how important the camera's white balance information is

---------- Post added 09-08-20 at 18:48 ----------

QuoteOriginally posted by Oldbayrunner Quote
Two things wrong with this; Lol
A. It's from DP review
B. It's from 2008
Time and model don't matter here. My example was to demonstrate the qualification and professionalism of programmers, not necessarily only at Pentax, but possibly everywhere else as well. Generally shouldn't trust the quality of files blindly, and always check for known bugs in the internet. Possibly there are other bugs or flaws in Pentax-generated DNGs not known yet, because they don't jump into anyones face, so nobody discovered them yet. Who knows... there's always such a possibility. The smaller a brand's user base, the higher is the likelihood of bugs being undiscovered.

Last edited by Frater; 08-09-2020 at 09:54 AM.
08-09-2020, 09:56 AM - 2 Likes   #18
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QuoteOriginally posted by Frater Quote
I thought these are basics, known since the beginnings of RAW files in the DSLR world
I think, perhaps, that more research might be done on your part. The absence of white balance in the recorded sensor output is a well-known attribute of RAW capture and one of the advantages of choosing that option. As for how the camera's white balance settings are provided to processing software, a bit of time with ExifTool might be helpful. The relevant tag name in the makernotes section is "White Point" and the value is 4 positive integers used for curve biasing.


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08-09-2020, 10:04 AM   #19
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Why can't people read. I said and still say, DNGs contain white balance. I didn't say and never said, that the raw pixel bits within a DNG would contain white balance. Instead, the DNG contain white balance by other means. They do that in specific tags. They don't do that in pixel bits. Did I already say, that DNG contain white balance?


Last edited by Frater; 08-09-2020 at 10:15 AM.
08-09-2020, 10:30 AM - 1 Like   #20
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QuoteOriginally posted by Frater Quote
Why can't people read. I said and still say, DNGs contain white balance. I didn't say and never said, that the raw pixel bits within a DNG would contain white balance. Instead, the DNG contain white balance by other means. They do that in specific tags. The don't do that in pixel bits. Did I already say, that DNG contain white balance?
Thanks for the clarification. I did read and took what I read at face value, that the white balance information in DNG from the K20D was "lost". In regards to the provided link. I went through the full thread carefully and found no reference to white balance information being lost in K20D DNG files, though I did find the comment copied below:

QuoteQuote:
Emphasis added is mine:

I have been using DNG until now because I am on CS2 and dont want to upgrade photoshop again. I seem to have to buy a new copy of photoshop every time I buy a new camera if I use PEF...

HOWEVER, the colour profile of the DNGs from the K20D have a problem. This has only been a minor issue until recently as you can set the white balance in the RAW convertor and correct. Even so, it is extra work I shouldnt have to do if I get it right the first time.

I recently took a bunch of shots at an indoor soccer party and the colour was just mad and no amount of work could correct it. The shots were unusable.

I now am going to shoot PEF and use the adobe RAW convertor to change them to DNG for processing. This will hopefully cure the colour problem and give me more shots per card into the bargain.
My reading is that the user's complaint had to do with poor color balance using available color (camera) profiles exposed by ACR for the DNG files and that they were correcting using white balance, but with mixed success.* They were hoping that converting PEF to DNG might solve that problem.

My skill with English is limited by my upbringing and education, but I don't read anything in the quoted post that indicates that white balance information was missing from the DNG that was present in the PEF.


Steve

* Given the mention of not wanting to constantly upgrade, I assume they meant the embedded profile provided by Pentax.

Last edited by stevebrot; 08-09-2020 at 10:35 AM. Reason: Clarity, grammar, and completeness
08-09-2020, 10:52 AM   #21
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OK then thanks for quoting the problem post.

But yes, white balance is still lost / wrong / unusable it's just not the explicit white balance tag then, but the implicit white balance embedded in the color profile, which destroys the resulting white balance alltogether.

QuoteOriginally posted by stevebrot Quote
HOWEVER, the colour profile of the DNGs from the K20D have a problem.
Actually, he points towards two problems.
1) The white balance problem (due to Pentax' bad color profile), but then
2) the Pentax bad color profile is also a problem in its own right, so that even manual white balance correction attempts don't rescue anything.

I wouldn't dare to trust Pentax-generated DNG files blindly, after reading about such issues? Not sure if Pentax budget situation allows them to afford much better programmers today, than they had during their best times (before they got sold to Hoya).
08-09-2020, 11:03 AM   #22
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QuoteOriginally posted by Frater Quote
Actually, he points towards two problems.
1) The white balance problem (due to Pentax' bad color profile), but then
2) the Pentax bad color profile is also a problem in its own right, so that even manual white balance correction attempts don't rescue anything.
We have a disconnect here. I suggest some research on the relationship of white balance to color profiles (DCP files). I found the page linked below to be helpful and have used the authors dcpTool software with good success as well.

DCP FIles

Have fun.

P.S. I have also found playing with Dave Coffin's dcraw to be helpful. With it, one can cook a DNG or PEF multiple different ways.

https://www.dechifro.org/dcraw/


Steve

(...FWIW, white balance is applied before the camera/color profiles...)


Last edited by stevebrot; 08-09-2020 at 11:10 AM.
08-09-2020, 11:14 AM   #23
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P.S. But should anybody confirm (explicitly for the K-70), that for K-70-generated DNG files there are at least no obvious consistency or completeness problems which would jump into your eye immediately, then Selvadero should be reasonable safe for now.

However, I don't recommend DNG. For me it is the software-dependent metadata workflow penalties associated with DNGs (I'm using Photoshop and Adobe's picture browser and metadata editor "Bridge" that comes with Photoshop) (but I'm using also ExifTool and also my powerful text editor for mass processing mass changes to my metadata whenever required) (that's actually another main reason for .xmp+raw files rather than .dng).

Even if you don't bother with playing around with your own metadata today - what if your requirements changes in the future? If you want to tag all your past work with locations, subjects, themes, persons, animals, or any other stuff related to whatever your favourite subject area has been?
Then you may be at a mess with having decided for the "wrong" format too early.


Mind also that DNG is not a guarantee to skip software updates. Even though that was one motivation behind DNG, in reality it may be (actually it is the case) for some software, that the first thing it does is to check the camera model recorded in the RAW or DNG metadata, and if it doesn't know that, it refuses the file. Even if the new camera didn't implement any relevant changes to the produced RAW or DNG content itself. Make sure you know how your favourite software behaves regarding new camera models.

Last edited by Frater; 08-09-2020 at 11:58 AM.
08-09-2020, 12:19 PM - 3 Likes   #24
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QuoteOriginally posted by Frater Quote
P.S. But should anybody confirm (explicitly for the K-70), that for K-70-generated DNG files there are at least no obvious consistency or completeness problems which would jump into your eye immediately, then Selvadero should be reasonable safe for now.

However, I don't recommend DNG. For me it is the software-dependent metadata workflow penalties associated with DNGs (I'm using Photoshop and Adobe's picture browser and metadata editor "Bridge" that comes with Photoshop) (but I'm using also ExifTool and also my powerful text editor for mass processing mass changes to my metadata whenever required) (that's actually another main reason for .xmp+raw files rather than .dng).

Even if you don't bother with playing around with your own metadata today - what if your requirements changes in the future? If you want to tag all your past work with locations, subjects, themes, persons, animals, or any other stuff related to whatever your favourite subject area has been?
Then you may be at a mess with having decided for the "wrong" format too early.


Mind also that DNG is not a guarantee to skip software updates. Even though that was one motivation behind DNG, in reality it may be (actually it is the case) for some software, that the first thing it does is to check the camera model recorded in the RAW or DNG metadata, and if it doesn't know that, it refuses the file. Even if the new camera didn't implement any relevant changes to the produced RAW or DNG content itself. Make sure you know how your favourite software behaves regarding new camera models.
I've done that with every digital camera I've owned that can shoot raw. Pentax DNG files have never presented me with any problems through the half dozen cameras I've shot with that create DNGs. Nor have I heard of anyone other than that one user having any sort of problems with DNG white balance.
Sorry, but one user of unknown skill level 12 years ago who had color balance issues under very suspect conditions, conditions where there were more than likely multiple white balances in the same frame, don't make for an especially lucid debating point regarding the usability of any given format.
08-09-2020, 02:20 PM - 1 Like   #25
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Just use DNG.....simples !
08-09-2020, 02:30 PM   #26
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The fact that Pentax has been messed up DNGs via writing corrupt or wrong color profiles once upon a time, that was just a side note, an anecdote, that things like this can happen.

The more important reasons against DNG (which made me deciding against it when the decision was due) are unrelated to that. They apply also to correct DNG files, regardless of which camera model or which brand produced it. They apply also to the perfect DNG files which Adobe's own DNG converter produces.

I'd warn about switching to DNG, if ALL of the following would be true
- you use Adobe products to process your RAWs
-- or you can't exclude that possibility for the future

- and, you are a metadata "power user" and you also use free "power tools" apart from what Adobe's user interfaces offer
-- or you can't exclude that possibility for the future

Else, DNG is probably fine. Just be aware, switching over to DNG limits your options what you can do in the future with your raw photos.
08-09-2020, 02:38 PM - 2 Likes   #27
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QuoteOriginally posted by Frater Quote
Just be aware, switching over to DNG limits your options what you can do in the future with your raw photos.
Sorry. Can you say that again?

Using a very common, open standard file format (DNG) limits your options in the future as opposed to using a single manufacturer proprietary format (PEF)?
08-09-2020, 02:44 PM   #28
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QuoteOriginally posted by bertwert Quote
Sorry. Can you say that again?

Using a very common, open standard file format (DNG) limits your options in the future as opposed to using a single manufacturer proprietary format (PEF)?
Yes, using a very common, open standard file format (DNG) limits your options in the future as opposed to using a single manufacturer proprietary format. Not generally, but in this instance.

This is because how Adobe software deals with Adobe's own DNG files, and how much of a problem this is for some "power user" workflows.
The Problem is not the DNG format as such (I like that), but the problem is Adobe's softwares' behaviour. Adobe software treats manufacturer proprietary formats much better and more appropriate than their own DNG format.

It is a bit like a man, who treats other women much better and more appropriate than his own wife
08-09-2020, 08:53 PM - 2 Likes   #29
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QuoteOriginally posted by bertwert Quote
Sorry. Can you say that again?

Using a very common, open standard file format (DNG) limits your options in the future as opposed to using a single manufacturer proprietary format (PEF)?
Bert, he is basing his premise on a single reported instance of a white balance failure in a situation where, most likely, white balance failure was guaranteed, and then doubling down with some unproven declaratives regarding Adobe.
This reads more like a hit piece on Pentax and Adobe than anything based even remotely on something resembling fact.
08-09-2020, 10:49 PM   #30
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QuoteOriginally posted by stevebrot Quote
(...FWIW, white balance is applied before the camera/color profiles...)
WB is applied after the DCP profile, when we are creating DCP we are not building that profile for the color of the light source we are doing so for the illuminate.
If WB was applied before the color profile we would need a different profile for daylight, overcast and shadow, and of course we do not need to do this
Here is a target shot in daylight and the shadows and developed using the same profile


The only difference is that the WB was set for the color temperature of the light.

---------- Post added 08-09-2020 at 10:59 PM ----------

QuoteOriginally posted by Frater Quote
But yes, white balance is still lost / wrong / unusable
In a DNG file the WB data is stored in C628 as multiplies for the 3 channels so that they achieve a WB
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