To enable end-to-end learning of defocus map estimation, a high-quality dataset is crucial. However, currently available datasets [29, 4] are not enough, as they are either for blur detection , instead of blur estimation, or of small size . To this end, we generate a defocus-blur dataset, which we call SYNDOF dataset. It would be almost impossible, even manually, to generate ground-truth defocus maps for defocused photos. So we use pinhole image datasets, where each image is accompanied by a depth map, to synthesize defocused images with corresponding ground-truth defocus maps.