converting Pentax RAW problem

[Sebastian Kraft-4]

Hello,

I have some trouble converting RAW files from a Pentax *ist DL2 camera.
You can see the problem here:

http://www.hey-you-freaks.de/photo/digikam_preview.jpg

This is how it looks like when I just watch the the picture with digikam.
After I load it with digikam to edit the image it opens the Color management
window. Thats OK. I have chosen SRGB for working space and the Pentax
profile from Bibble as input profile. But this is what I get:

http://www.hey-you-freaks.de/photo/digikam_raw.jpg

Colors are really bad. This occurs with every RAW file I load. Most times
the result is acceptable, but it always has the same red tint...

What has gone wrong here? I really want to get high quality 16bit TIFFS from
my camera...

Sebastian

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[Sebastian Kraft-4]

http://www.hey-you-freaks.de/photo/digikam_without_CM.jpg

This is the converted RAW without any color management and converted in 8bit
mode. It's different, but far away from good.

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Hi Sebastian,

when you load a raw image directly with the editor the gamma is not set,
meaning that the original linear curve of the cameras sensor is used.
You can either shape the lightness correction curve to a convex form
(last tab in the CM dialog). Or, which is easier,  use the
Lightness/Contrast/Gamma filter afterwards and set the gamma to a value
usually between 1.8 and 2.2. You may have to enhance the contrast
afterwards. See the attachment. This is your raw image with gamma=2.2
and contrast=80.

Btw. I'm of the opinion, that opening a raw in the editor should set
gamma and contrast to a reasonable value by default (or at least ask the
user). I recently reported this as a bug, so I suggest you vote for it:

http://bugs.kde.org/show_bug.cgi?id=146393

CU
Martin.


Sebastian Kraft wrote:

> http://www.hey-you-freaks.de/photo/digikam_without_CM.jpg
>
> This is the converted RAW without any color management and converted in 8bit
> mode. It's different, but far away from good.
>
> _______________________________________________
> Digikam-users mailing list
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> https://mail.kde.org/mailman/listinfo/digikam-users
>  

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Hi Sebastian,

when you load a raw image directly with the editor the gamma is not set,
meaning that the original linear curve of the cameras sensor is used.
You can either shape the lightness correction curve to a convex form
(last tab in the CM dialog). Or, which is easier,  use the
Lightness/Contrast/Gamma filter afterwards and set the gamma to a value
usually between 1.8 and 2.2. You may have to enhance the contrast
afterwards. Find your raw image with gamma=2.2 and contrast=80 here:

http://www.flickr.com/photo_zoom.gne?id=535788069&size=o

Btw. I'm of the opinion, that opening a raw in the editor should set
gamma and contrast to a reasonable value by default (or at least ask the
user). I recently reported this as a bug, so I suggest you vote for it:

http://bugs.kde.org/show_bug.cgi?id=146393

CU
Martin.


Sebastian Kraft wrote:

> http://www.hey-you-freaks.de/photo/digikam_without_CM.jpg
>
> This is the converted RAW without any color management and converted in 8bit
> mode. It's different, but far away from good.
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>  

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[Gilles Caulier-4]

2007/6/8, Martin Schmettow <[hidden email]>:

Hi Sebastian,

when you load a raw image directly with the editor the gamma is not set,
meaning that the original linear curve of the cameras sensor is used.
You can either shape the lightness correction curve to a convex form
(last tab in the CM dialog). Or, which is easier,  use the
Lightness/Contrast/Gamma filter afterwards and set the gamma to a value
usually between 1.8 and 2.2. You may have to enhance the contrast
afterwards. Find your raw image with gamma= 2.2 and contrast=80 here:

http://www.flickr.com/photo_zoom.gne?id=535788069&size=o

Btw. I'm of the opinion, that opening a raw in the editor should set
gamma and contrast to a reasonable value by default (or at least ask the
user). I recently reported this as a bug, so I suggest you vote for it:

http://bugs.kde.org/show_bug.cgi?id=146393

The reason that RAW 8 bits gamma is correct at loading in editor and not RAW 16 bits is duing to dcraw itself.

Look the dcraw web project page : in  16bits color depth,  RAW are converted in linear mode without gamma correction. In 8 bits, the gamma is automaticly corrected. This is why 16 bits color depth RAW file imported come become too black...

I don't know why Dave have not add an option to auto-correct gamma with 16 bits color depth. The user must always has the possibility to do it.

Of course we can do it in digiKam automaticly, but if dcraw can do it instead, like it do it with 8 bits color depth, this will be more homogenous...

Gilles

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[Sebastian Kraft-4]

Martin Schmettow wrote:

> Hi Sebastian,
>
> when you load a raw image directly with the editor the gamma is not set,
> meaning that the original linear curve of the cameras sensor is used.
> You can either shape the lightness correction curve to a convex form
> (last tab in the CM dialog). Or, which is easier,  use the
> Lightness/Contrast/Gamma filter afterwards and set the gamma to a value
> usually between 1.8 and 2.2. You may have to enhance the contrast
> afterwards. Find your raw image with gamma=2.2 and contrast=80 here:
>
> http://www.flickr.com/photo_zoom.gne?id=535788069&size=o
>

Ok... I know... I can adjust gamma, contrast.. but the result is far from
acceptable.
This is how the simple preview JPEG looks like:
http://www.hey-you-freaks.de/photo/digikam_preview.jpg
And even this is ways better than anything digikam gives me.

there must be some other way?

Sebastian


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Sorry, I cannot agree. Your preview image is a bit to dark, it lacks
details in the mirroring water surface. Colors are not vivid. Be
reminded, that the preview image was produced by your camera, not Digikam.
Also consider, that the edited version I uploaded was produced quickly
from a Jpeg, which is only 8bit. You can expect better results
(especially more details in the dark parts) from your raw image. Try it
with L/C/G filter. Digikam brings all filters needed to produce good
results from raw images, if you know what you're doing.

--Martin.

Sebastian Kraft wrote:

> Martin Schmettow wrote:
>
>  
>> Hi Sebastian,
>>
>> when you load a raw image directly with the editor the gamma is not set,
>> meaning that the original linear curve of the cameras sensor is used.
>> You can either shape the lightness correction curve to a convex form
>> (last tab in the CM dialog). Or, which is easier,  use the
>> Lightness/Contrast/Gamma filter afterwards and set the gamma to a value
>> usually between 1.8 and 2.2. You may have to enhance the contrast
>> afterwards. Find your raw image with gamma=2.2 and contrast=80 here:
>>
>> http://www.flickr.com/photo_zoom.gne?id=535788069&size=o
>>
>>    
>
> Ok... I know... I can adjust gamma, contrast.. but the result is far from
> acceptable.
> This is how the simple preview JPEG looks like:
> http://www.hey-you-freaks.de/photo/digikam_preview.jpg
> And even this is ways better than anything digikam gives me.
>
> there must be some other way?
>
> Sebastian
>
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>  

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[Sebastian Kraft-4]

It is difficult to argue about that, but the preview image from
digikam/camera looks just like the scene was in reality. The converted RAW
file has wrong colors. Other RAW converters like Bibble do it right.
There is definitely something wrong with digikam.
Perhaps your right and I have done something wrong while conversion, but I
tried several hours and read a lot about that and couldn't get a result
that is acceptable.
The problem with color is with every picture, but mostly it is hard to see.
This picture with the wood and the water extremly shows the problem. I have
used digikam for months and created a lot of good looking pictures with it
using the same procedure as with the picture we are talking about here. So
I think I'm not doing it completely wrong...


Sebastian

> Sorry, I cannot agree. Your preview image is a bit to dark, it lacks
> details in the mirroring water surface. Colors are not vivid. Be
> reminded, that the preview image was produced by your camera, not Digikam.
> Also consider, that the edited version I uploaded was produced quickly
> from a Jpeg, which is only 8bit. You can expect better results
> (especially more details in the dark parts) from your raw image. Try it
> with L/C/G filter. Digikam brings all filters needed to produce good
> results from raw images, if you know what you're doing.
>
> --Martin.
>
> Sebastian Kraft wrote:
>> Martin Schmettow wrote:
>>
>>  
>>> Hi Sebastian,
>>>
>>> when you load a raw image directly with the editor the gamma is not set,
>>> meaning that the original linear curve of the cameras sensor is used.
>>> You can either shape the lightness correction curve to a convex form
>>> (last tab in the CM dialog). Or, which is easier,  use the
>>> Lightness/Contrast/Gamma filter afterwards and set the gamma to a value
>>> usually between 1.8 and 2.2. You may have to enhance the contrast
>>> afterwards. Find your raw image with gamma=2.2 and contrast=80 here:
>>>
>>> http://www.flickr.com/photo_zoom.gne?id=535788069&size=o
>>>
>>>    
>>
>> Ok... I know... I can adjust gamma, contrast.. but the result is far from
>> acceptable.
>> This is how the simple preview JPEG looks like:
>> http://www.hey-you-freaks.de/photo/digikam_preview.jpg
>> And even this is ways better than anything digikam gives me.
>>
>> there must be some other way?
>>
>> Sebastian
>>
>>
>> _______________________________________________
>> Digikam-users mailing list
>> [hidden email]
>> https://mail.kde.org/mailman/listinfo/digikam-users
>>

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Am Freitag 08 Juni 2007 schrieb Sebastian Kraft:
> It is difficult to argue about that, but the preview image from
> digikam/camera looks just like the scene was in reality. The converted RAW
> file has wrong colors. Other RAW converters like Bibble do it right.

Hmm, I don't know how much "RAW" the raw format of your Pentax is but I know
much about Canons raw format CRW/CR2 And there are e.g. no whitebalance,
color temp or gamma information part of the raw data. You only have metatags
to give some hints how the photo looks like and the built-in raw-jpg
converter generates an embedded preview.
But raw means here Its up to you how to interpret the raw data.

Can you put a raw file online so its possible to play with it?

Bye

  Thorsten
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[Sebastian Kraft-4]

Thorsten Schnebeck wrote:
> Hmm, I don't know how much "RAW" the raw format of your Pentax is but I
> know much about Canons raw format CRW/CR2 And there are e.g. no
> whitebalance, color temp or gamma information part of the raw data. You
> only have metatags to give some hints how the photo looks like and the
> built-in raw-jpg converter generates an embedded preview.

white balance helped a lot. I knew that other converters set WB value
to Camera WB and haven't thought about this. Digikam does this only when you
open white balance dialog.
After working with WB, L/C/G and saturation results where ok.
So in part it was my fault... But I think digikam should give more support
to the user with creating some good presets, or a good looking image right
after opening it. It's not fair to always compare with Bibble or
Rawtherapee, but with them I open the file and it is quite well :)
But they don't have the ability to organize my pictures as well as digikam
does...

> But raw means here Its up to you how to interpret the raw data.
>
> Can you put a raw file online so its possible to play with it?
>

Here it is:(~10MB)
http://www.hey-you-freaks.de/photo/imgp2711.pef
Perhaps you can get it better? Please tell me your settings...

Thanks so far,

Sebastian

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Hi Sebastian,

now I fully agree with you. Raw image handling, neither single nor
batch, is not sufficient at the moment. This is why I usually use Bibble
to do a rough conversion (to 16bit png) and digikam for management and
advanced image editing.

You could vote for these bugs:
https://bugs.kde.org/show_bug.cgi?id=124814
https://bugs.kde.org/show_bug.cgi?id=146393

--Martin.

Sebastian Kraft schrieb:
> white balance helped a lot. I knew that other converters set WB value
> to Camera WB and haven't thought about this. Digikam does this only when you
> open white balance dialog.
> After working with WB, L/C/G and saturation results where ok.
> So in part it was my fault... But I think digikam should give more support
> to the user with creating some good presets, or a good looking image right
> after opening it.


--
begin:vcard
fn:Martin Schmettow
n:Schmettow;Martin
org:University Passau;Chair of Information Systems II
adr:;;Innstr. 43;Passau;;94032;Germany
email;internet:[hidden email]
title:PhD Student
x-mozilla-html:FALSE
url:http://www.wi.uni-passau.de/
version:2.1
end:vcard


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[Arnd Baecker]

On Fri, 8 Jun 2007, Martin Schmettow wrote:

> Hi Sebastian,
>
> when you load a raw image directly with the editor the gamma is not set,
> meaning that the original linear curve of the cameras sensor is used.
> You can either shape the lightness correction curve to a convex form
> (last tab in the CM dialog). Or, which is easier,  use the
> Lightness/Contrast/Gamma filter afterwards and set the gamma to a value
> usually between 1.8 and 2.2. You may have to enhance the contrast
> afterwards. See the attachment. This is your raw image with gamma=2.2
> and contrast=80.
>
> Btw. I'm of the opinion, that opening a raw in the editor should set
> gamma and contrast to a reasonable value by default (or at least ask the
> user). I recently reported this as a bug, so I suggest you vote for it:
>
> http://bugs.kde.org/show_bug.cgi?id=146393

Well, that bug is closed, because it is fixed in current svn.

Martin, have you tried the svn version?

Best, Arnd

> Sebastian Kraft wrote:
> > http://www.hey-you-freaks.de/photo/digikam_without_CM.jpg

I get:

The requested URL /photo/digikam_without_CM.jpg was not
found on this server.

> > This is the converted RAW without any color management and converted in 8bit
> > mode. It's different, but far away from good.
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