1. An apparatus for processing a light field image, the apparatus comprising: a lens; a mask configured to spatially modulate four-dimensional (4D) light field data of a scene passing through the lens such that the spatially modulated 4D light field data includes wideband information of the scene, the mask comprising a transparent layer, and a metal layer disposed on the transparent layer, the metal layer comprising an attenuation pattern configured to attenuate light passing through the transparent layer; a sensor configured to detect a two-dimensional (2D) image corresponding to the spatially modulated 4D light field data; and a data processing unit configured to recover the 4D light field data from the 2D image, generate a high-resolution depth map based on the 4D light field data, and generate an all-in-focus image based on the 2D image and the high-resolution depth map, wherein the attenuation pattern comprises unit patterns, each unit pattern comprises a 7×7 pixel structure, and each region in the second and fourth rows and second and fourth columns of the unit patterns are configured to intercept light.