std::vector<std::string> items;
    std::vector<const Exiv2::TagInfo*> tags;
    tags.push_back( Exiv2::ExifTags::ifdTagList() );
    tags.push_back( Exiv2::ExifTags::exifTagList() );
    tags.push_back( Exiv2::ExifTags::iopTagList() );
    tags.push_back( Exiv2::ExifTags::gpsTagList() );
    for (std::vector<const Exiv2::TagInfo*>::iterator it = tags.begin(); it != tags.end(); ++it ) {
        while ( (*it)->tag_ != 0xffff ) {
            items.push_back( Exiv2::ExifKey( (*it)->tag_, Exiv2::ExifTags::ifdItem( (*it)->ifdId_ ) ).key() );
            ++(*it);
        }
    }