The Sigma 15mm F2.8 EX DG is a fisheye for full-frame digital reflex camera. It has a maximum aperture of F2.8 and provides a rectangular image. It is also compatible with APS-C cameras. Solid construction. The panoramas are beautiful, but it takes more pictures, more images have to be processed in post-production, but also requires a little more time to spend in the adjustment of images to make the pano. For this panoramic image with the Canon EOS 5D Mark III, I made 6 photos at 30 degrees upwards and another 6 at 30 degree downward.