Review on Canon TS-E 17mm f/4L UD Aspherical: The Ultimate Tilt-Shift Lens for Canon DSLRs by Jason Spainhour

I can only agree with the previous reviews. A little pricey but great quality so I think you get what you pay for. Not only is there no filter or lens hood, but because of the round front element, it's easy to touch with your fingers without having to pay attention. In addition, it's just great for photographing architectural interiors. Highly recommended.