Re: Exif makernotes not shown?

["Jef Driesen" <jefdriesen hotmail com>]

Lutz Müller wrote:
> On Fri, 2006-08-04 at 08:57 +0200, Jef Driesen wrote:
> > http://users.telenet.be/sacn/tmp/IMG_3485_small.jpg (resized, 61KB)
>
> lutz lutz:~$ exif --show-mnote DSC/IMG_3485_small.jpg

When I run this command on my system, I get very different results:

jef manta:~$ exif --show-mnote IMG_3485_small.jpg
MakerNote contains 19 values:
Settings (first part): Settings (first part)
(null):
(null):
Settings (second part): Settings (second part)
(null):
Image type: Image type
Firmware version: Firmware version
Image number: Image number
Owner name: Owner name
(null):
(null):
(null):
(null):
(null):
(null):
(null):
(null):
(null):
(null):
Segmentation fault

So there is certainly something wrong here. I compiled libexif from
source (version 0.6.13) and the result is very similar:

jef manta:~$ exif --show-mnote IMG_3485_small.jpg
MakerNote contains 95 values:
Macro mode: Macro mode
Self time: Self time
Quality: Quality
Flash mode: Flash mode
Continuous drive mode: Continuous drive mode
Settings (first part): Settings (first part)
Focus mode: Focus mode
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Image size: Image size
Easy shooting mode: Easy shooting mode
Settings (first part): Settings (first part)
Contrast: Contrast
Saturation: Saturation
Sharpness: Sharpness
ISO: ISO
Metering mode: Metering mode
Focus type: Focus type
AF point selected: AF point selected
Exposure mode: Exposure mode
Settings (first part): Settings (first part)
Lens type: Lens type
Long focal length of lens: Long focal length of lens
Short focal length of lens: Short focal length of lens
Focal units per mm: Focal units per mm
Maximal aperture: Maximal aperture
Settings (first part): Settings (first part)
Flash activity: Flash activity
Flash details: Flash details
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Focus mode: Focus mode
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Zoomed resolution: Zoomed resolution
Zoomed resolution base: Zoomed resolution base
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Color tone: Color tone
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
Settings (first part): Settings (first part)
(null):
(null):
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
White balance: White balance
Settings (second part): Settings (second part)
Sequence number: Sequence number
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
AF point used: AF point used
Flash bias: Flash bias
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Subject distance: Subject distance
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
Settings (second part): Settings (second part)
(null):
Image type: Image type
Firmware version: Firmware version
Image number: Image number
Owner name: Owner name
(null):
(null):
(null):
(null):
(null):
(null):
(null):
(null):
(null):
(null):

> I guess the problem is that EOG does not explicitly scan the MakerNote.
> You need to patch EOG to use exif-data.h/exif_data_get_mnote_data and
> the functions in exif-mnote-data.h. However, I am not sure that you
> really want to show above results to an ordinary user. IMHO there is
> some work to be done in libexif to fully understand the content of the
> MakerNote.

I don't know if EOG is explicitly scanning the MakerNote I assumed it
did, because it does shows an empty MakerNote section. And for gthumb, I
found a bug (http://bugzilla.gnome.org/show_bug.cgi?id=316665) where
this problem was also reported. It says the issue is fixed, but also no
MakerNotes here.

I think it is worth showing this kind of data, because for instance my
camera only stores the ISO value in the MakerNote. And that is certainly
valuable data for a photographer.

Is there some documentation how to add extra MakerNote tags to libexif?
Because if I can have those tags shown in the applications I use, and
the libexif implementation is not too difficult to learn, I don't mind
to spend some time on it.