I am wondering why these lenses are so cheap in comparison to the actual selling price. Is this normal and does anyone not recomend an online transaction. http://www.amazon.com/Canon-28-135m...ZPY06LT1N&s=electronics&qid=1191266189&sr=1-9 http://www.amazon.com/Canon-70-200m...ZPY06LT1N&s=electronics&qid=1191266189&sr=1-6 The reviews are great from other buyers. I am still affraid! Thanks in advance for any imput.