1. An image processing method comprising: acquiring an original image and a disparity map, the disparity map indicating distribution of disparity values associated with respective pixels in the original image; causing a processor to decide a dynamic range of disparity on the basis of the acquired original image and the acquired disparity map; and converting the disparity map in a manner that each disparity in the disparity map is distributed within the decided dynamic range of the disparity; wherein the dynamic range of the disparity is decided on the basis of distribution of maximum disparity amounts and the disparity map, the distribution of the maximum disparity amounts being based on a relationship between a crosstalk degradation amount corresponding to contrast according to a spatial frequency of the original image, and a disparity transition.