I got a fisheye lens and it was mighty expensive. Its a Japan optics HD digital advance 0.48x52mm. Im using it on my Nikon D3100 18-55mm lens and it never focusses. Ever. I've tried many things (auto/manual focus, 3D setting etc) but nothing seems to work. Are there any suggestions? It worked when the guy at the store demo'd it to me.
Read more: Blurry Fish Eye Lens Photos?