This is an exceptional quality fisheye lens. It has a gental rectangular distortion at 17, and a full fisheye-quality distortion at 10. Easy to use, clear, bright shots. Requires sufficient lighting for good clear photographs - daylight or external flash required for lower light situations. Cap stays on firmly when not being used. Does not come with any filters though, like most Nikon fisheye lenses do. I love this lens and use it more than I thought I would -- and the shots are always among the best sellers from my event photography. Highly recommended. [...].