Originally posted by eagle_fly Do you think that a company that cannot solve a known problem for nearly two years can prosper in the long run?
I notice that you never posted an image to actually show your problem, so I have some doubts about your problem report.
People in the past have confused dust and dirt for stains, and when they posted an image here it was pretty easy to see what the real problem was - stains or not. If it was indeed stains, people here would help you confirm that. Folks want to help, not score points.
In the absence of evidence of a real problem, your original post and all your other conclusions about Pentax are suspect.