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Conversion to DNG vs keeping PEF files

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marko61

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Hopefully a quick question: Is anything lost in when using Photo Browser to convert Pentax raw format to dng files? I've noticed when opening the dng files in Elements that the white balance is often considerably different to a) the view in photo lab & b) how things looked at the time. Can this always be fixed with some work on the temperature/gray point or is the conversion from pef to dng making decisions about how the image should look in the same way that saving to jpeg accepting the default settings, or indeed shooting in jpeg mode does?

It suits my workflow (I use this term in a rather loose sense) better to use the bulk conversion offered by Photo Browser to create a jpeg & dng file then delete the pef. Viewing can then be done in Bridge with editing for the best shots in Elements. Whilst Photo Lab isn't horrendous to use, I do prefer the layout, & certain features of Elements for looking at the raw files but if I'm ditching the pefs I want to be sure that I'm not losing any information from the raw file.

Thanks in advance.

Mark
 
Apologies - meant to add that search is not working & I have trawled through a few pages to see if I could find a thread which would answer this. I do remember seeing discussions about using dng files but they seemed to concentrate more on the file sizes involved & which package made the best conversion from raw to jpeg/tiff rather than the specifics of the conversion process and dangers it may present.

thanks
 
And as much pixel peeping as I have done, I can find no differences. It might lose some camera setting flags that the Pentax and other software makes use of, but nothing that I have noticed with the software that I use.
 
I'll try to keep the answers short, as follows:
marko61 said:
Hopefully a quick question: Is anything lost in when using Photo
Browser to convert Pentax raw format to dng files? I've noticed
when opening the dng files in Elements that the white balance is
often considerably different to a) the view in photo lab & b) how
things looked at the time. Can this always be fixed with some work
on the temperature/gray point or is the conversion from pef to dng
making decisions about how the image should look in the same way
that saving to jpeg accepting the default settings, or indeed
shooting in jpeg mode does?
Click to expand...
No, nothing is lost by a Pentax software conversion from PEF to DNG, as they "know" their own format, but some raw convertors don't know how to read the resulting DNG files properly (although they may also not know how to read the PEF's properly either). You didn't say what camera you have. If you have a K10D, there was an issue with not properly handling WB until you update to ACR version 3.7. It's a free update, and I think it works with Elements, although you didn't say what version of Elements you have. If you have an earlier version of Elements that doesn't work with newer ACR versions, then you will likely always have this WB discrepency, as ACR only correctly works with WB for cameras in it's database.

Yes, this can be fixed by work on the colour temperature/grey point, although you may have to ignore the absolute values for colour temperature and tint as they may be incorrect. No, no decisions are being made about image developement in the conversion from PEF to DNG, and the original raw data is preserved completely intact. Just the critical information used to develop the image to a RGB representation is "tagged" differently.
marko61 said:
It suits my workflow (I use this term in a rather loose sense)
better to use the bulk conversion offered by Photo Browser to
create a jpeg & dng file then delete the pef. Viewing can then be
done in Bridge with editing for the best shots in Elements. Whilst
Photo Lab isn't horrendous to use, I do prefer the layout, &
certain features of Elements for looking at the raw files but if
I'm ditching the pefs I want to be sure that I'm not losing any
information from the raw file.
Click to expand...
I haven't used PhotoBrowser. Does it generate DNG's that are at least as small as the PEF's you want to throw away?

Hope this helps, GordonBGood
 
GordonBGood wrote:
[snip]
GordonBGood said:
If you have a K10D, there was an
issue with not properly handling WB until you update to ACR version
3.7. It's a free update, and I think it works with Elements,
although you didn't say what version of Elements you have. If you
have an earlier version of Elements that doesn't work with newer
ACR versions, then you will likely always have this WB discrepency,
as ACR only correctly works with WB for cameras in it's database.
Click to expand...
[snip]

ACR 3.7 works with Elements 4 and 5, not earlier.
 
GordonBGood said:
marko61 said:
Hopefully a quick question: Is anything lost in when using Photo
Browser to convert Pentax raw format to dng files? I've noticed
when opening the dng files in Elements that the white balance is
often considerably different to a) the view in photo lab & b) how
things looked at the time. Can this always be fixed with some work
on the temperature/gray point or is the conversion from pef to dng
making decisions about how the image should look in the same way
that saving to jpeg accepting the default settings, or indeed
shooting in jpeg mode does?
Click to expand...
No, nothing is lost by a Pentax software conversion from PEF to
DNG, as they "know" their own format, but some raw convertors don't
know how to read the resulting DNG files properly (although they
may also not know how to read the PEF's properly either). You
didn't say what camera you have. If you have a K10D, there was an
issue with not properly handling WB until you update to ACR version
3.7. It's a free update, and I think it works with Elements,
although you didn't say what version of Elements you have. If you
have an earlier version of Elements that doesn't work with newer
ACR versions, then you will likely always have this WB discrepency,
as ACR only correctly works with WB for cameras in it's database.

Yes, this can be fixed by work on the colour temperature/grey
point, although you may have to ignore the absolute values for
colour temperature and tint as they may be incorrect. No, no
decisions are being made about image developement in the conversion
from PEF to DNG, and the original raw data is preserved completely
intact. Just the critical information used to develop the image to
a RGB representation is "tagged" differently.
GordonBGood said:
It suits my workflow (I use this term in a rather loose sense)
better to use the bulk conversion offered by Photo Browser to
create a jpeg & dng file then delete the pef. Viewing can then be
done in Bridge with editing for the best shots in Elements. Whilst
Photo Lab isn't horrendous to use, I do prefer the layout, &
certain features of Elements for looking at the raw files but if
I'm ditching the pefs I want to be sure that I'm not losing any
information from the raw file.
Click to expand...
I haven't used PhotoBrowser. Does it generate DNG's that are at
least as small as the PEF's you want to throw away?
Click to expand...
No, the DNG's made by PhotoBrowser are uncompressed full 16 bit files at around 20MB, the ones from the camera discard the unused 4 bits and are smaller.

If you use ACR or the Adobe DNG converter to compress either the Photobrowser, or in-camera DNGs, they both compress to the same file size, PhotoBrowser can see an embedded thumbnail in the compressed DNG files but cannot open a larger size, or report any EXIF info, nor can Pentax PhotoLab convert compressed DNG's, only uncompressed or in-camera (discsrded 4 bit) DNG's.

If you save the DNG's in ACR or the Adobe DNG converter (from either PPB or Camera) in uncompressed format, they end up as full 16 bit files of around 20MB. Pentax PhotoBrowser and PhotoLab can work with these files.

ACR or Lightroom gives different colours to that obtained from Pentax PhotoLab with any Raw file format, their profiling is quite different. If you calibrate the colour profile sliders in ACR/Lightroom to match a particular image produced by PhotoLab, it will (almost always) not match another shot using the same slider settings. If you create a profile from a Greytag chart, it still doesn't give, to my eye (on calibrated CRT and printers), satisfactory results. That's why I (and a few others) don't use any Adobe Raw converters.

The nearest converters to Pentax PhotoLab colours that I have tried are (in order):

SilkyPix (happy with any format of PEF or DNG - my preference)
Capture One v 3.7.7 (PEF only)
Bibble (PEF and native Pentax DNG only)

There are a few others I haven't extensively tried besides the above and Adobes' offerings.

There are many other aspects to the IQ produced by different converters besides colour, as well as interfaces and workflow. Everyone has their own preferences. ;-)
--
Richard Day - 'Carpe Diem!'
Gloucester UK
 
I don't know about the conversion by Pentax Photo Lab, and to be honest I never used it.

However, when importing images into Adobe Photoshop Lightroom, I do convert the PEFs to DNGs on import. This results in files another bit smaller than the PEFs, and as such this is the most friendly on my disk space. Doing the same with in-camera DNGs doesn't result in the files being converted, so in that case you retain the much larger DNGs that come out of the camera (larger than the PEFs too), unless you convert separately using the DNG converter. No image quality loss that I detected either way.

Wim

--
Belgium, GMT+1

 
Thank's for the summary, Richard.

Interesting comments on the colour treatment by ACR, as I've also found some strange anomalies in ACR colour profiling that makes me start to doubt their colour modeling.

Strange that so many so-called DNG conversions don't support loss-less compression, and some not even for reading (Pentax Photo Browser). It isn't that hard to do.

Regards, GordonBGood
richardday said:
No, the DNG's made by PhotoBrowser are uncompressed full 16 bit
files at around 20MB, the ones from the camera discard the unused 4
bits and are smaller.

If you use ACR or the Adobe DNG converter to compress either the
Photobrowser, or in-camera DNGs, they both compress to the same
file size, PhotoBrowser can see an embedded thumbnail in the
compressed DNG files but cannot open a larger size, or report any
EXIF info, nor can Pentax PhotoLab convert compressed DNG's, only
uncompressed or in-camera (discsrded 4 bit) DNG's.

If you save the DNG's in ACR or the Adobe DNG converter (from
either PPB or Camera) in uncompressed format, they end up as full
16 bit files of around 20MB. Pentax PhotoBrowser and PhotoLab can
work with these files.

ACR or Lightroom gives different colours to that obtained from
Pentax PhotoLab with any Raw file format, their profiling is quite
different. If you calibrate the colour profile sliders in
ACR/Lightroom to match a particular image produced by PhotoLab, it
will (almost always) not match another shot using the same slider
settings. If you create a profile from a Greytag chart, it still
doesn't give, to my eye (on calibrated CRT and printers),
satisfactory results. That's why I (and a few others) don't use any
Adobe Raw converters.

The nearest converters to Pentax PhotoLab colours that I have tried
are (in order):

SilkyPix (happy with any format of PEF or DNG - my preference)
Capture One v 3.7.7 (PEF only)
Bibble (PEF and native Pentax DNG only)

There are a few others I haven't extensively tried besides the
above and Adobes' offerings.

There are many other aspects to the IQ produced by different
converters besides colour, as well as interfaces and workflow.
Everyone has their own preferences. ;-)
Click to expand...
 
GordonBGood said:
Strange that so many so-called DNG conversions don't support
loss-less compression, and some not even for reading (Pentax Photo
Browser). It isn't that hard to do.
Click to expand...
Especially since it's the same compression that Canon uses - dcraw uses the same code to uncompress either format.

--
John Bean [BST/GMT+1] ('British Stupid Time')

PAW 2007 Week 19:
http://waterfoot.smugmug.com/gallery/2321711/2/151841141/Large



Index page: http://waterfoot.smugmug.com
Latest walkabout (21 March 2007):
http://waterfoot.smugmug.com/gallery/2641073
 
Should have stated at the outset that I'm using K100D with Elements 4 on a Mac.

I had a brief look at my copy of Elements before leaving for work this morning and it appears I'm running 4.0 but would need 4.01 for the Camera Raw 4.0 update to work. Checked Elements for updates & it said none were available so it seems to think it's up to date. The 3.7 version Gordon mentions seems to be for Windows.

So despite Richard's complaints that they never match, I think I'm right in saying everyone agrees that there's no damage/loss to the file during the conversion. Therefore with some tweaking of temperature, tint etc the image can be worked on to successfully look as the subject did when it was taken.

Thanks for the replies. Third time I've posted a question here & third time I've received quick & helpful responses.

Cheers
 
John Bean (UK) said:
GordonBGood said:
Strange that so many so-called DNG conversions don't support
loss-less compression, and some not even for reading (Pentax Photo
Browser). It isn't that hard to do.
Click to expand...
Especially since it's the same compression that Canon uses - dcraw
uses the same code to uncompress either format.
Click to expand...
Also considering that Pentax PhotoLab uses the SilkyPix engine, you would expect similar compatability. As Gordon would probably say, it is slipshod programming!

As you know, SilkyPix has no issues with any of the three DNG file formats from a K10D/ACR conversion, i.e.

16 bit uncompressed (i.e. PEF -> DNG with PhotoBrowser or ACR uncompressed)
12 bit uncompressed (from K10D native DNG)
12 bit compressed (Any format to ACR DNG compressed)

I do notice one small thing in Silkypix. When moving from one image to the next in the split screen (browser) mode, it takes longer (about 3 to 4 secs) to display the main image from a compressed file than a uncompressed file (about 1 sec), despite the files being larger. I can only surmise that SilkyPix takes a while to deal with the compression methodology.

Once you have viewed the file and go back, it is almost instant for up to 5 files, once you go past 5, the first file of the string is dumped in favour of the newest, if you then go back to the original, it takes the same time to display as it originally did. It is one of the many items on my "improvements list" that will shortly be going to ISL.
--
Richard Day - 'Carpe Diem!'
Gloucester UK
 
GordonBGood said:
Thank's for the summary, Richard.

Interesting comments on the colour treatment by ACR, as I've also
found some strange anomalies in ACR colour profiling that makes me
start to doubt their colour modeling.
Click to expand...
Some of us have doubted this for some time, I don't think that John Bean, Steve Jacob and Barry Pearson would mind me mentioning their names. My apologies for not mentioning the many others who also have the same view.
GordonBGood said:
Strange that so many so-called DNG conversions don't support
loss-less compression, and some not even for reading (Pentax Photo
Browser). It isn't that hard to do.
Click to expand...
Indeed, especially as they use the SIlkypix engine which does!
--
Richard Day - 'Carpe Diem!'
Gloucester UK
 
Wim, is compression default when importing any DNG or PEf, or is it an option ?

lock
 
richardday said:
John Bean (UK) said:
GordonBGood said:
Strange that so many so-called DNG conversions don't support
loss-less compression, and some not even for reading (Pentax Photo
Browser). It isn't that hard to do.
Click to expand...
Especially since it's the same compression that Canon uses - dcraw
uses the same code to uncompress either format.
Click to expand...
Also considering that Pentax PhotoLab uses the SilkyPix engine, you
would expect similar compatability. As Gordon would probably say,
it is slipshod programming!
Click to expand...
No, I wouldn't expect it. The "engine" is only used for the raw data conversion, all the file handling is done by the same clunky Pentax software that's always been there.
richardday said:
As you know, SilkyPix has no issues with any of the three DNG file
formats from a K10D/ACR conversion
Click to expand...
As far as I know Silkypix has no problems with almost any DNG file, even those from cameras it doesn't recognise at all.

--
John Bean [BST/GMT+1] ('British Stupid Time')

PAW 2007 Week 19:
http://waterfoot.smugmug.com/gallery/2321711/2/151841141/Large



Index page: http://waterfoot.smugmug.com
Latest walkabout (21 March 2007):
http://waterfoot.smugmug.com/gallery/2641073
 
John Bean (UK) said:
richardday said:
John Bean (UK) said:
GordonBGood said:
Strange that so many so-called DNG conversions don't support
loss-less compression, and some not even for reading (Pentax Photo
Browser). It isn't that hard to do.
Click to expand...
Especially since it's the same compression that Canon uses - dcraw
uses the same code to uncompress either format.
Click to expand...
Also considering that Pentax PhotoLab uses the SilkyPix engine, you
would expect similar compatability. As Gordon would probably say,
it is slipshod programming!
Click to expand...
No, I wouldn't expect it. The "engine" is only used for the raw
data conversion, all the file handling is done by the same clunky
Pentax software that's always been there.
Click to expand...
LOL!
John Bean (UK) said:
John Bean (UK) said:
As you know, SilkyPix has no issues with any of the three DNG file
formats from a K10D/ACR conversion
Click to expand...
As far as I know Silkypix has no problems with almost any DNG file,
even those from cameras it doesn't recognise at all.
Click to expand...
Indeed, I regard it as my Swiss Army knife Raw converter! If we could get them to incorporate a few more refinements and a proper English interface and manual, I believe it would be even better and much more popular. It deserves it.
--
Richard Day - 'Carpe Diem!'
Gloucester UK
 
John Bean (UK) wrote:
[snip]
John Bean (UK) said:
As far as I know Silkypix has no problems with almost any DNG file,
even those from cameras it doesn't recognise at all.
Click to expand...
The only "significant" one I know of is that it can only handle 3 colours. So it can't handle either a raw DNG or a linear DNG for the Sony F828.

It is a lesson to just about all other companies about how to handle DNG, and how to document it fully instead of glibly.
 
Barry Pearson said:
Barry Pearson said:
As far as I know Silkypix has no problems with almost any DNG file,
even those from cameras it doesn't recognise at all.
Click to expand...
The only "significant" one I know of is that it can only handle 3
colours. So it can't handle either a raw DNG or a linear DNG for
the Sony F828.

It is a lesson to just about all other companies about how to
handle DNG, and how to document it fully instead of glibly.
Click to expand...
Just so, but it's a pity it doesn't support XMP, that is another one of my "wishes".
--
Richard Day - 'Carpe Diem!'
Gloucester UK
 
richardday wrote:
[snip]
richardday said:
Just so, but it's a pity it doesn't support XMP, that is another
one of my "wishes".
Click to expand...
I agree. I am a fan of DNG, but I think "XMP within DNG" (in a sensible way) is actually the most important aspect of this.
 
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