An apparatus for acquiring images includes an image sensor and a signal processor. The image sensor may include a sensor substrate and a color separation lens array, wherein the sensor substrate includes a plurality of photo-sensing cells, and the color separation lens array may separate an incident light into a plurality of lights having different wavelengths and forms a phase distribution for condensing the plurality of lights having the different wavelengths on adjacent photo-sensing cells of the plurality of photo-sensing cells. The signal processor may perform deconvolution on sensing signals of the plurality of photo-sensing cells to obtain a sub-sampled image, perform demosaicing to restore a full resolution image having a full resolution from the sub-sampled image, and correct a color of the full resolution image using a point spread function (PSF) of the color separation lens array.