oldest_datetime_config

# Save as .ExifTool_config in you home directory so that exiftool can read this
%Image::ExifTool::UserDefined = (
    'Image::ExifTool::Composite' => {
        # Select oldest date from a number of date tags
        OldestDateTime => {
            Desire => {
                0 => 'FileModifyDate',
                1 => 'MDItemFSContentChangeDate',
                2 => 'FileCreateDate',
                3 => 'MDItemFSCreationDate',
                4 => 'ModifyDate',
                5 => 'CreateDate',
                6 => 'DateTimeCreated',
                7 => 'DateTimeOriginal',
                8 => 'GPSDateTime',
                9 => 'CreationDate'
            },
            ValueConv => q{
                my $oldest = undef;
                for my $date (@val) {
                    next if not defined $date or $date lt '1970:01:02';
                    $date =~ s/([+-]\d{2}:\d{2}$)|([A-Z]{3}$)|([Z]$)//; # Strip TimeZone 2018:12:24 10:57:48'-05:00' or 2018:10:18 07:19:58'Z or EDT'
                    if ($date && (!$oldest || $date lt $oldest)) {
                        $oldest = $date;
                    }
                }
                $oldest =~ s/([+-]\d{2}:\d{2}$)|([A-Z]{3}$)|([Z]$)//;
                return $oldest;
            },
            PrintConv => '$self->ConvertDateTime($val)',
        },
    },
);

1;