My replaced 7700 is showing up with the same blotches as my previous 7700. This seemed to happen after cleaning the lens with compressed air and a lens cloth. The blotch gets bigger when I increase the image size, but stay in the same place when I invert the image. Is this dust inside the lens or is it finger print marks? Its strange because the blotches are in the same place as before only a bit higher up the screen.... please help as I'm really regrating going the PJ route now PS other than compressed air and lens cloth is there anything else I can use to get the blotches out? Like a special liquid of some sort?