^ listen to claussen. All i use is century optics, and thats all anyone that i know uses if their shooting professionally. They have the best optical glass, best/most durable construction, and from what ive experienced, an amazing anti-glare coating (at least on my fisheye). Think of it this way, your buying a lens from the same company that makes optical pieces for 100 grand hd cameras, film cameras, and projection lenses for feature films. id put my trust in them any day.
one thing, their caps suck, haha i bought a 700 dollar fisheye, and the lens cap never fits on, but thats just a joke im making