The Sigma AF 10mm F2.8 EX DC Fisheye HSM is a fast superwide-angle lens of the diagonal FishEye type with a hyper sonic motor AF drive. It has been specially designed for small-format digital SLR cameras and cannot be used on full-format and film cameras.
The diagonal FishEye produces a full-frame image with barrel distortion, exaggerated perspective and angle of view of 180°, which is beyond human eye's ability. Only Nikon sensor allows you to get a 180 ° image, other sensors are smaller in size and their angle of view are a bit smaller as well. The lens has a very large depth of field.