At that price is simply unbeatable. The construction, materials, the handling is impeccable. Mounted on a D5100, it has control in the viewfinder of the development, the pilot diaphragm device. the image quality is very good at F5.6. This goal will ask you a little time to tame distortion FishEye. Essential goal in his bag if you have a Nikon APS-C. I will take this brand to other focal.