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02-02-2009, 02:29 PM   #1
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RAW Processing in Linux

Hello,
this is my first post on pentaxforums.

I published a test to (roughly) compare a few software available in Linux to convert RAW (PEF) to JPG.

It's not a scientific nor a super-accurate test, but just a first test to show the outcome of the following programs saving the photos "as is" without manipulations.

The software under test were:
  • K20D's internal JPG processor
  • Pentax Photo Laboratory (wine)
  • RAW Therapee
  • UFRaw
  • Rawstudio

At a first sight, the best outcome is the JPG processed by the camera.

I published the photos of the test in the Italian Pentax forum.

Here's the link:
Pentaxiani, il forum: Leggi argomento - TEST: conversione da PEF a JPG in Linux

soprano

02-02-2009, 03:23 PM   #2
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I think the one from the camera looks very blue — the others are all much warmer.

But in general, the problem I have under Linux with RAW is lack of good ICC profiles for the camera. I wish Pentax would make these available!
02-02-2009, 03:39 PM   #3
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QuoteOriginally posted by soprano Quote
test to show the outcome of the following programs saving the photos "as is" without manipulations.
what is the point to test "as is" ?
02-02-2009, 03:47 PM   #4
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One thing you need to be aware of is that UFRaw applies no sharpening at all to the image. I believe all the others do some sharpening.

02-02-2009, 03:55 PM   #5
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QuoteOriginally posted by mattdm Quote
I think the one from the camera looks very blue — the others are all much warmer.
?? In my screen the first one (the one from the camera) is the warmer and the others are blueish...

QuoteOriginally posted by mattdm Quote
But in general, the problem I have under Linux with RAW is lack of good ICC profiles for the camera. I wish Pentax would make these available!
Actually PPL, Rawstudio and UFRaw supports Pentax's ICC profiles and should read them from the RAW.
02-02-2009, 03:59 PM   #6
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QuoteOriginally posted by deejjjaaaa Quote
what is the point to test "as is" ?
"as is" in the sense that such programs should read camera's white balance ICC profile and generate JPGs which should be comparable each other.
This may be important, for example, for someone not willing to fine-tune each generated JPG and batch-process all together.

Anyway, do you have a preference among those software?
02-02-2009, 04:14 PM   #7
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QuoteOriginally posted by RBellavance Quote
One thing you need to be aware of is that UFRaw applies no sharpening at all to the image. I believe all the others do some sharpening.
right, UFRaw has no sharpening (unless used as a Gimp plugin), Rawstudio has default sharpening to zero, raw therapee has some default sharpening (deselectable), and PPL reads sharpening level from PEF (default in the KD20 is +1).
02-02-2009, 04:28 PM   #8
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Have you looked at Bibble?
They have a Linux version.

I know it's not free, but it's a linux tool anyway!

02-02-2009, 05:01 PM   #9
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QuoteOriginally posted by soprano Quote
Actually PPL, Rawstudio and UFRaw supports Pentax's ICC profiles and should read them from the RAW.
This is the first time I hear anyone mention the presence of an ICC profile in the Pentax raw files (or any other manufacturer's, as a matter of fact). Are your sure about that ?
02-02-2009, 06:59 PM   #10
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QuoteOriginally posted by RBellavance Quote
This is the first time I hear anyone mention the presence of an ICC profile in the Pentax raw files (or any other manufacturer's, as a matter of fact). Are your sure about that ?
If you try to change the various settings on the camera (sharpness, saturation, white balance etc.), then make a RAW picture, copy the PEF on your disk and open it with Pentax Photo Laboratory then all the settings on the camera are automatically used by the program. Means such metadata is stored in the PEF. I guess other programs (Rawstudio and UFRaw?) are at least using part of the metadata as well.

From Raw image format - Wikipedia, the free encyclopedia :
«the structure of raw files often follow a common pattern that is:
-etc..
-Camera sensor metadata which is required to interpret the sensor image data. This includes the size of the sensor, the attributes of the CFA and its color profile
-etc..»

EDIT: I checked around, and while PEF specification is not provided by Pentax, DNG specification clearly includes a couple of tags for the purpose: AsShotPreProfileMatrix and AsShotICCProfile:
http://www.adobe.com/products/dng/pdfs/dng_spec.pdf

@YJD: I downloaded and installed Bibble, and indeed it seems to be an excellent program. I'll test it deeply next days.

Last edited by soprano; 02-02-2009 at 07:42 PM.
02-02-2009, 07:43 PM   #11
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QuoteOriginally posted by soprano Quote
If you try to change the various settings on the camera (sharpness, saturation, white balance etc.), then make a RAW picture, copy the PEF on your disk and open it with Pentax Photo Laboratory then all the settings on the camera are automatically used by the program. Means such metadata is stored in the PEF. I guess other programs (Rawstudio and UFRaw?) are at least using part of the metadata as well.
I agree with that, but this is not evidence of an embedded ICC profile.
02-03-2009, 02:02 AM   #12
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QuoteOriginally posted by RBellavance Quote
I agree with that, but this is not evidence of an embedded ICC profile.
Does "AsShotICCProfile" represent an evidence that the ICC profile may be embedded in the raw?
02-03-2009, 05:59 AM   #13
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QuoteOriginally posted by soprano Quote
Does "AsShotICCProfile" represent an evidence that the ICC profile may be embedded in the raw?

I've never seen such an EXIF field in a PEF (or DNG) file. Maybe it is new in the K20D ? Good move by Pentax if that is the case !

Anyway, I stand corrected it seems. Sorry for arguing with you, then.
02-05-2009, 02:44 PM   #14
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The K20D Jpeg is totally burnt out in the higlights above the eyes - no details left
PPL and RT restore the details and the colour in the highlights
UFRaw and RawStudio have the same burnout as the JPEG, but I suspect you did not use auto-exposure and highlight restore in either.

All in all, you cannot compare raw programs without getting to know them a little and all are made for tweaking. If you do not want to tweak obviously PPL is the best choice together with RT only RT introduces some loss of detail due to the way it handles sharpening and NR.

UFRaw, when used correctly (and DCRAW) will produce results that blow the JPEG out of the water.

Any way you choose is a matter of taste but the gap between JPEG and raw is unsurmountable.
02-05-2009, 02:58 PM   #15
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I just want to point out that it's a bit misleading calling the "original K20D" versions that. They are converted to JPEG using digiKam's RAW converter (look at the exif). And digiKam uses either LittleCMS, dcraw or LibRaw depending on the version you're running so there's really nothing "original" about it. You would need to compare against a shot taken using RAW+ from the camera to compare an "original" JPEG against RAW conversions.

And as mentioned, Bibble was left out of the comparision as well as LightZone. Both of which have their own RAW converters with at least native K10D ICC support built in; in the case of LightZone version 3.6 fully supports the K20D DNG & PEF formats.

edit: I may have mis-spoken at least in part. I see now in the EXIF it has the JPG extension on the filename:
# ? (0x000b) = digiKam-0.9.4
# Image Width = 4672 pixels
# Image Length = 3104 pixels
# Unknown tag: Tagnum = 0x010d ===> data = IMGP0299.JPG
Still, why run the photo through digiKam at all if it was an in-camera JPEG?

Last edited by Venturi; 02-05-2009 at 03:03 PM. Reason: clarification
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