public function getFocalLength()
    {
        if (!isset($this->data[self::FOCAL_LENGTH])) {
            return false;
        }

        return $this->data[self::FOCAL_LENGTH];
    }
public function getFocalLength()
    {
        if (!isset($this->data[self::FOCAL_LENGTH])) {
            return false;
        }

        return $this->data[self::FOCAL_LENGTH];
    }
public function getFocalLength ( ) { if ( ! isset ( $ this -> data [ self :: FOCAL_LENGTH ] ) ) { return false ; } return $ this -> data [ self :: FOCAL_LENGTH ] ; }
Returns the focal length in mm, if it exists

@return float|boolean
Returns the focal length in mm if it exists