1. An imaging apparatus, comprising: an imager which captures a target scene including a plurality of objects in such a manner that a same object comes into focus and a depth of field is different, so as to acquire a first image signal and a second image signal representing two scene images; an image creator which creates a third image signal by subjecting the first image signal to a process for reducing a level of the first image signal; and a composite image creator which creates a composite image signal by adding the first image signal to the third image signal in such a manner that a ratio of the third image signal to the first image signal is increased as a difference of a high frequency component between the first image signal and the second image signal increase.