segun parece la limpieza del sensor de la 400D solo es una estrategia de mercadeo que lo unico que hace es retrasar unos dias la llevada al centro de servicio, yo creo que el sistema de limpieza de sensor no es de mucha utilidad, que piensa la general? / as it seems the cleaning of the alone sensor of 400D is only a marketing strategy that the only thing that makes is to retard some days the one taken to the center of service, do I believe that the system of sensor cleaning is not of a lot of utility that she/he thinks the general one?