1. An imaging apparatus comprising: a photometry section that performs photometry of a subject; an exposure calculating section that sets exposure conditions based on results of the photometry of said photometry section; an imaging section that images said subject in accordance with said exposure conditions to generate image data; a smoothing processing section that performs smoothing processing on said image data generated in said imaging section and generates a smoothed image; a gain map generating section that generates a gain map according to luminance component of said smoothed image generated by said smoothing processing section, the gain map being derived from a gain amount added for each pixel; and an image processing section that performs an image correction to improve luminosity in a dark region by multiplying a gain to each pixel of said image data generated in said imaging section using said gain map generated in said gain map generating section, wherein said exposure calculating section determines said exposure conditions according to correction setting of said image correction in said image processing section.