Does anybody else have any noticeable dust behind the front element. I have a little dot dead center, it's noticeable if i stand under my ceiling light. Ive tried cleaning, and its not on the surface, so I'm pretty sure it's a trapped dust particle. Is that common? I assume that Canon's Malaysian factories don't have quite the quality control of their Japanese ones. If not, is it worth returning? I only ask because I had a zillion issues getting the lens the first time (first the shipper shipped it to the wrong address, then the package got lost by fedex, then there was a delay shipping out the replacement, etc....) I don't want to go through the trouble if it's a common issue that won't effect image quality, especially for such a cheap lens that's basically just a placeholder until Canon releases the 50mm 1.4 IS.