An imaging apparatus according to one embodiment comprises an imaging element, a photographing optical system, an imaging control section, a first projection converting section, composing section, and a second projection converting section. The first projection converting section converts a first projection images into second projection images, respectively, each of which is an image of a second projection system in which a variation of a change amount of an image height on an imaging plane to a change amount of an entrance angle of the light into the photographing optical system is smaller than that of the first projection image. The composing section composes the second projection images to acquire a composed image. The second projection converting section converts the composed image into an image of a projection system different from the second projection system.