[Digikam-users] dynamic range problem

Gilles Caulier caulier.gilles at gmail.com
Tue Oct 7 09:19:52 BST 2008


2008/10/7 mfi <mfi at go2.pl>

> Hello,
>
>
>
> Gilles Caulier pisze:
> > Michael,
> >
> > I cannot reproduce the problem here.
> >
> > I have tested to import your RAW file using digiKam for KDE4
> > (0.10.0-beta4) or digiKam for KDE3 (0.9.5-svn) using new RAWImport
> > tool for image editor, and all work fine with highlight recovery
> settings.
> >
> > For RAW file decoding, i use libkdcraw based on LibRaw
> > (http://www.libraw.org). LibRaw currently use the last dcraw code for
> > demosaicing. Now look my screenshots:
> >
> > * This the preview of raw import tool with RAW demosaicing settings.
> > Postprocessing use default settings (no gamma/curve/exposure
> > adjustment) . Of course like it's a preview with a divided by 4 image
> > size, huge zooming give artifact. But it's enough to set demosaicing
> > configuration. Also, working on a reduced raw decoded image speedup
> > computation. Note that i use 16 bits color depth, not 8 (it's a non
> > sence to use 8 bits color depth with RAW)
> >
> >
> http://digikam3rdparty.free.fr/Screenshots/temp/rawimport/pef-rawimport-preview.png
>
>
> Is that possible in version 9.4 ? I am not familiar with svn and there's
> no KDE 4 for gentoo at this moment. I can't see Raw Import Tab in my
> digikam and I don't have options that You have below histogram. If this
> is just version related problem I can wait a bit for a more current
> release for my distro. I tried sharpening tool for digikam and now I
> just don't want to use other program ;)


Raw Import  tool do not exist with 0.9.4. Only current code from svn (coming
with next 0.9.5 release) has this code.

You can customize highlight recovery level in Raw decoding settings panel,
but this config is common for all RAW files to load in editor. You cannot
customize it like with RAW Import.

Also, 0.9.4 use old dcraw based libkdcraw. 0.9.5 use new version with
LibRaw: it's more powerfull.


>
> >
> > And now, the best: the full raw image in editor. Look like the color
> > (white balance) is better than RAW studio !
> >
> > http://digikam3rdparty.free.fr/Screenshots/temp/rawimport/pef-editor.png
> >
> > For me, it's a good example how to use properly RAW files in digiKam.
> The white balance in RawStudio is messed up, but it's my fault - I set
> it up manually,  just to show the problem with highlights.
>
> >
> > Note : the preview from digiKam  icon view is rendered using JPEG
> > preview image from RAW file. It's not RAW image data decoded. In fact
> > the preview  JPEG  is adjusted using camera  firmware. It's still JPEG
> > : only 8 bits color depth ! this is why highlight are broken, and it's
> > a good example to explain why RAW is always better than JPEG.
>
> But highlights are broken after RAW decoding as far as I understand...


Not here.


>
> Preview (didn't know RAW contains jpg previevs, thanks)


RAW is a container : JPEG, RAW image, ICC profile, metadata data (Exif +
makernotes), Gamma curves, etc...


> is rendered
> correctly and highlights aren't broken there... Did I miss something ?
> >
>

I think no, but it's not easy to investiguate whithout more info.

Can you take a screencast of you digikam session, including RAW setting and
RAW loading in editor ? Best tool for that is recordmydesktop...

Gilles
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