3. A jure, if the penalty is specified in the law itself, as either latae or ferendae sententiae; ab homine, if a penalty is inflicted by means of a special precept or condemnatory sentence of a judge, though the punishment is prescribed in law ; wherefore a penalty ferendae sententiae attached to a law is a jure tantum before the condemnatory sentence, after the sentence it is both a jure and ab homine but is considered as ab homine. A penalty is always understood to be ferendae sententiae, unless the law explicitly states that it is latae sententiae, or that it is incurred ipso facto, or ipso jure, or if other similar terms are employed. (Canon 2217.)
You just proved Caminus correct, ferendae means you need a judge to determine.