[Digikam-devel] reading lens description

[Gilles Caulier]

2009/1/21 Matthias Welwarsky <matze at welwarsky.de>

> On Wednesday 21 January 2009 14:51:17 Gilles Caulier wrote:
> > 2009/1/21 Matthias Welwarsky <matze at welwarsky.de>
> >
> > > On Wednesday 21 January 2009 12:59:45 Matthias Welwarsky wrote:
> > > > On Wednesday 21 January 2009 09:41:30 Gilles Caulier wrote:
> > > > > ok. your new lens descriptio ntag for panasonic camera is recorded
> to
> > > > > DMetadata.
> > > > >
> > > > > Question : why you have set this change :
> > > > >
> > > > > +++ digikam-0.10.0-beta8/libs/dmetadata/dmetadata.cpp    2009-01-19
> > > > > 21:47:42.000000000 +0100
> > > > > @@ -105,7 +105,7 @@
> > > > >
> > > > >          if (identify.exposureTime != -1.0)
> > > > >          {
> > > > > -            convertToRational(1/identify.exposureTime, &num, &den,
> > > > > 8); +            convertToRational(identify.exposureTime, &num,
> &den,
> > > > > 8); setExifTagRational("Exif.Photo.ExposureTime", num, den, false);
> }
> > > >
> > > > Because otherwise the exposure time shows up as "40s" instead of
> > > > "1/40s". Might be a speciality of this camera particular camera, or a
> > > > bug in
> > >
> > > dcraw?
> > >
> > > > However, ufraw does it correctly, and Marcel Wiesweg wrote:
> > > > > Thanks, but that's already fixed in SVN ;-)
> > > >
> > > > So I assume it's actually a digikam bug which is already fixed.
> > >
> > > Which reminds me of something: The aperture is also incorrectly read
> from
> > > these RAW files. A photo was shot with f/10, but digikam reports f/32.
> Is
> > > this
> > > also fixed already, by chance?
> >
> > No. This is a problem in Exiv2 library which is used by digiKam to handle
> > Raw metadata.
>
> Not sure. It looks like Exiv2 doesn't at all handle Panasonics new "RW2"
> files
> and it falls back to using DMetadata::loadUsingDcraw(), which in turn uses
> KDcrawIface::KDcraw::rawFileIdentify().


Libraw can handle some metadata, but it's not perfect as Exiv2 do. If Exiv2
cannot do it, Libraw is used instead.

I CC Alex Tutubalin (from LibRaw project) here for informations.


> > Which version do you use ?
>
> Hm. Whatever ships with kubuntu 8.10. I'll have a look when I'm back home.


I recommend to use last Exiv2 0.18.

If it doesn't work with RW2, try current implementation from svn.

I CC Andreas Huggel (from Exiv2 project) here for info.

In all case, It mus work with Exiv2. If i doesn't, open a new Exiv2 bug
report.


>
> >
> > Note : digikam do not use dcraw to play with Raw image data, but libraw.
>
> ... and libraw is based on dcraw, I know.


And new version 0.7.0 start to implement new demosaising methods different
than dcraw, with better results.

 Gilles Caulier
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.kde.org/pipermail/digikam-devel/attachments/20090121/f221ca80/attachment.html>