Workaround for Sigma 8-16mm requested

[linuxuser]

There is a known bug for the Sigma 8-16mm F4.5-5.6 DC HSM, below 10mm the focal length is zero, but a workaround can be coded. Maybe there should be a fix through exiftool?

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[EXIF]          0x920a Focal Length                    : 0.0 mm
[EXIF]          0xa405 Focal Length In 35mm Format     : 0 mm
[MakerNotes]    0x001d Focal Length                    : 0.0 mm
[Composite]          - Focal Length                    : 0.0 mm (35 mm equivalent: 0.0 mm)

There is 2nd field with Focal Length in the makernotes:

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[MakerNotes]    0x0009 Focal Length                    : 8.1 mm

How can I get the value of 0x0009?

Similar is this:

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[MakerNotes]    0x0000 Lens Type                       : Sigma 8-16mm F4.5-5.6 DC HSM
[MakerNotes]    0x0001 Lens Type                       : Sigma 8-16mm F4.5-5.6 DC HSM
[Composite]          - Lens ID                         : Sigma 8-16mm F4.5-5.6 DC HSM

But that is not actually a problem.

If you need a sample let me know.

[Phil Harvey]

Try this to fix the metadata in these files:

exiftool -n '-focallength<copy1:focallength' -if '$focallength==0 and $copy1:focallength!=0' FILE

where FILE is one or more file and/or directory names.  (The above quoting is for Mac/Linux.  Windows users would need double quotes.)

I think this should work, but I can't test it without a sample.

- Phil

Edit: If "copy1" doesn't work, try "copy2".  Use this command to see which:

exiftool -a -G4 -focallength FILE

[linuxuser]

Sorry, I was away and I have troubles with my internet too. I will send you a sample ASAP. Thanks!

[linuxuser]

Please check your mails, I have sent to you:
Subject: Sample files  - Workaround for Sigma 8-16mm requested
Date: Wed, 24 Sep 2014 19:29:46 +0200

The sample files contain photos in PEF-format with these focal lengths:

8.1 mm
8.8 mm
9.4 mm
10.0 mm
10.6 mm
11.2 mm
11.9 mm
13.1 mm
13.8 mm
15.0 mm
16.2 mm

10mm is ok, but below the focal length is missing with exif.

What I would need is a variable vor a bash-script with the correct focal length, which can be used later to write more new exif-data. The condtion, if the focal length is 0, I would set with my own script, except you correct this with exiftool automatically. If you check the web, this is a general problem with this lens.

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exiftool -a -G4 -focallength 10.0_mm.pef
[]              Focal Length                    : 10.0 mm
[Copy1]         Focal Length                    : 10.0 mm
[Copy2]         Focal Length                    : 10.0 mm

Thanks for having a look into it!

[Phil Harvey]

I haven't got the mails yet.  I'll let you know when I receive them, but if it isn't soon I'll have to take a look at them tomorrow.  The queensu mailserver implements a grey list that often delays mails by an hour or so.

- Phil

[Phil Harvey]

I got your files.  The command I suggested works if you change "copy1" to "copy2" in both arguments.

- Phil

[linuxuser]

I got your files.  The command I suggested works if you change "copy1" to "copy2" in both arguments.

- Phil

Phil, could you please give me the syntax to get the focal length as a bash-variable, as mentioned before? I don't need / want to use copy

I mean something like this:

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exiftool -s -s -s -n -focallength 8.1_mm.pef
0

But the result should be 8.1

[Phil Harvey]

exiftool -s -s -s -n -copy2:focallength 8.1_mm.pef

Edit: Removed unnecessary -a option from command.

[linuxuser]

Thanks, great!

[linuxuser]

I was so happy that it worked, so I forget to ask, that I understand this syntax better.

I always thought, that I have to use something like  -MAKERNOTES:focallength, but you use -a

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exiftool -s -s -s -n -a -focallength 8.1_mm.pef
0
0
8.125

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exiftool -s -s -s -n -a -makernotes:focallength 8.1_mm.pef
0
8.125

I still don't understand why it is copy2. Can this be found out with trial and error only?

[Phil Harvey]

It is copy2 because it is the 3rd tag extracted with the same name.  To figure out which one is correct for an image, use -a -G4 when extracting.

- Phil

[linuxuser]

Now I understand, the 1st match is the original and doesn't count for copy. Thanks!

[linuxuser]

Not using exiftool 10.40.

I think there was a change with exiftool so the above doesn't work anymore. It could be a longer time ago, since I don't use an 8mm lens very often.

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ExifTool Version Number         : 10.40

exiftool -H -a -G4 original.pef | grep -i focal
[]              0x001d Focal Length                    : 0.0 mm
[]              0x0003 SR Focal Length                 : 10 mm
[]              0x0009 Lens Focal Length               : 8.1 mm
[]              0xa405 Focal Length In 35mm Format     : 0 mm
[]                   - Focal Length                    : 0.0 mm (35 mm equivalent: 0.0 mm)
[]                   - Hyperfocal Distance             : 0.00 m

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exiftool -a -G -H original.pef | grep -i focal
[EXIF]          0xa405 Focal Length In 35mm Format     : 0 mm
[MakerNotes]    0x001d Focal Length                    : 0.0 mm
[MakerNotes]    0x0003 SR Focal Length                 : 10 mm
[MakerNotes]    0x0009 Lens Focal Length               : 8.1 mm
[Composite]          - Focal Length                    : 0.0 mm (35 mm equivalent: 0.0 mm)

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exiftool -a -G4 -H original.pef | grep -i copy
[Copy1]         0x8827 ISO                             : 400
[Copy1]         0x9204 Exposure Compensation           : +0.7
[Copy1]         0x9207 Metering Mode                   : Multi-segment
[Copy1]         0x0012 Exposure Time                   : 1/160
[Copy1]         0x0013 F Number                        : 8.0
[Copy1]         0x001f Saturation                      : 0 (normal)
[Copy1]         0x0020 Contrast                        : 0 (normal)
[Copy1]         0x0021 Sharpness                       : 0 (normal)
[Copy1]         0x0001 EV Steps                        : 1/3 EV Steps
[Copy1]         0x000e Sensitivity Steps               : As EV Steps
[Copy1]         0x0001 Lens Type                       : Sigma 8-16mm F4.5-5.6 DC HSM
[Copy1]         0x0000 Pentax Model ID                 : K-5 II
[Copy1]         0xa403 White Balance                   : Auto
[Copy1]         0x0100 Image Width                     : 160
[Copy1]         0x0101 Image Height                    : 120
[Copy1]         0x0103 Compression                     : JPEG (old-style)
[Copy1]         0x011a X Resolution                    : 300
[Copy1]         0x011b Y Resolution                    : 300
[Copy1]         0x0128 Resolution Unit                 : inches
[Copy2]         0x0100 Image Width                     : 4928
[Copy2]         0x0101 Image Height                    : 3264
[Copy2]         0x0103 Compression                     : JPEG (old-style)
[Copy2]         0x011a X Resolution                    : 300
[Copy2]         0x011b Y Resolution                    : 300
[Copy2]         0x0128 Resolution Unit                 : inches


In a bash-script the variable is empty

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EXIFFOCALLENGTH_APS=`exiftool -s -s -s -n -a -copy2:focallength "$TEMPFILE"`

[Phil Harvey]

Sorry for the inconvenience; a few Pentax tags were renamed in ExifTool 10.01.  Now things are better and you can just use "LensFocalLength" (a more robust solution than relying on a specific copy number).

- Phil

[linuxuser]

Thanks, and sorry I didn't notice the change of the tags. It works again. Which other Pentax-Tags have been renamed? Maybe you have a link? http://www.exiftool.org/TagNames/Pentax.html shows all tags.

BTW Phil, did you test samples from the new Pentax KP already? http://www.us.ricoh-imaging.com/index.php/cameras/pentax-kp