problem with Nikon nefs

[Alan Clifford]

Hi Phil.

I have a problem with nefs that I don't have with jpegs using nikon:timezone#

I've created a short example

use strict;
use warnings;

# my $photofilespec = './dsc_8635.nef' ;
# my $photofilespec = './dsc_8635.jpg' ;
my $photofilespec = './ahc_1177.nef' ;
# my $photofilespec = './ahc_1177.jpg' ;
# my $photofilespec = './ahc_0559.nef' ;

use Image::ExifTool;
my $n_exifTool = new Image::ExifTool;
my @n_dtotags = (  'exif:DateTimeOriginal', 'nikon:timezone#',
    'nikon:daylightsavings#', 'nikon:datetimeoriginal' );
my $n_dtoinfo = $n_exifTool->ImageInfo($photofilespec, \@n_dtotags) ;

print STDERR "\$\$n_dtoinfo{\$n_dtotags[0]} =  $$n_dtoinfo{$n_dtotags[0]}\n" ;
print STDERR "\$\$n_dtoinfo{\$n_dtotags[1]} =  $$n_dtoinfo{$n_dtotags[1]}\n" ;



This results in

Code Select Expand


alan@coprolith:timezonetest$ perl debugit.pl
$$n_dtoinfo{$n_dtotags[0]} =  2011:02:28 18:07:50
$$n_dtoinfo{$n_dtotags[1]} =  2011:02:28 18:07:50


whereas the command line

exiftool -exif:DateTimeOriginal -nikon:timezone# -nikon:daylightsavings# -nikon:datetimeoriginal ahc_1177.nef


gives

Code Select Expand


Date/Time Original              : 2011:02:28 18:07:50
Timezone                        : -180
Daylight Savings                : 1


With a jpg created from the nef, the code works as expected

Code Select Expand


alan@coprolith:timezonetest$ perl debugit.pl $$n_dtoinfo{$n_dtotags[0]} =  2011:02:28 18:07:50
$$n_dtoinfo{$n_dtotags[1]} =  -180




Alan

[Phil Harvey]

Hi Alan

This will happen if there are multiple EXIF:DateTimeOriginal tags.

I would normally suggest setting Duplicates to 0, but since you want a specific group this won't work because your tag may get hidden by another group.

You could either check the tag name or call GetInfo separately for each tag to be sure you get the right one.

- Phil

[Alan Clifford]

Thanks,  I'll try that.

Alan

[Phil Harvey]

Hi again Alan,

Thinking about this again, I think I was wrong about the Duplicates option hiding other tags -- this only happens when extracting tags for an entire group with GROUP:all.

So just setting Duplicates to 0 may solve the problem after all.

- Phil

[Phil Harvey]

Hi Alan,

I'm back on my computer so I can look into this in detail and give a definitive answer today.  (Yesterday I was replying from my iPod.)

Setting Duplicates to 0 does solve your problem.

- Phil

Edit: I have updated the description of the "ARRAY ref" argument in the ImageInfo documentation to try to explain this.

[Alan Clifford]

Setting Duplicates to 0 does solve your problem.

- Phil

Thanks Phil, I was just about to query that.

I saw using the command line tool with -a -G that there are two exif:datetimeorginals (I wonder why) but this code was OK

$n_exifTool->Options(Duplicates => 0);
my @n_dtotags = (  'exif:DateTimeOriginal', 'nikon:timezone#',
    'nikon:daylightsavings#', 'xmp:DateTimeOriginal' );

avoiding one of the exifs but getting the xmp

Alan