public static int defineTag(int ifdId,short tagId){
  return (tagId & 0x0000ffff) | (ifdId << 16);
}

public static int defineTag ( int ifdId , short tagId ) { return ( tagId & 0x0000ffff ) | ( ifdId << 16 ) ; }
returns the constant representing a tag with a given tid and default ifd .
