A dynamic range enhancement method and apparatus for an imaging device expands a dynamic range of an input image without an associated increase in the amount of image calculations. The dynamic range enhancement method includes producing brightness information and color information from an input image; applying gamma correction and inverse gamma correction to the brightness information to produce a gamma corrected image and an inverse gamma corrected image; comparing variances of the gamma corrected image and the inverse gamma corrected image at identical spots; and expanding a dynamic range of the input image by selecting one of the variances at each spot. The dynamic range of an input image is expanded by applying a post imaging process without increasing calculation amount of the imaging device.