1. A stereo three-dimensional (3D) image capturing method of a single lens auto focus camera, comprising the steps of: a) taking plural multi-focus images; b) estimating said plural multi-focus images to obtain a depth map and an all-in-focus image; c) mixing said depth map with plural background depth maps to obtain a mixed depth map; d) obtaining respectively a left image for left eye of user and a right image for right eye of user by means of depth image based rendering (DIBR); and e) outputting said left image and said right image onto a 3D display.