I'd strongly suggest a matte box for two reasons.
!) To protect the lens from damage.
2) To stop flare.
You've got a number of options for a matte box, ranging from very cheap to very expensive. If you look around dvxuser.com there was/is a foldup unit made of fabric being advertised there. We have one and it works quite well given the cost. Beyond that there are the formatt matte boxes that'll work well with the correct rings but getting up in price. For the ultimate fix Chroziel are the way to go.
Bob.