A mobile device comprising a processor configured to merge a plurality of images each having a distinct focus position in a scene to generate a focus-stacked image that encompasses all focus positions of the plurality of images. Also, an apparatus comprising a camera configured to capture a plurality of color images for one scene each with a distinct focus distance and a processor configured to register the plurality of color images to generate a plurality of registered color images, generate a plurality of luminance (Y) channels from the plurality of registered color images, and stack the plurality of Y channels to generate a focus-stacked Y channel.