http://www.dchome.net/viewthread.php?tid=999546&extra=page%3D1
(in Chinese, Google Translation to English Here)

The user confirms that his K-5 *Did* Not have any problem before and there was only dusts seen. The UFO only appears more recently, after 4 months of light use, for taking about 5k photos, it is told.
Really really too bad.. Even not to mention that this is a really annoying issue, indeed the resale value of any K-5 is endangered, undoubtedly! >:-( Just like the Pentax SDM, it seems that the life-time of it is just too short and rather limited, before that the most feared and infamous issue would happen some days later, maybe just in the near future! :-o
Btw, I think Pentax' last official statement for that "this will be covered by the warranty" is just worthless and helpless. It is because this is a product defect without any doubt, could they escape from the warranty liability in the end anyway?? >:-{
For still being without any good explanation to the root cause of this problem from the Pentax side, I think no Pentaxian will have the full confidence to purchase a new K-5 without any worry and hesitation after all! Especially considering the numerous reports of the same (sensor "stains") case worldwide already and its re-occurrence (no matter for new replacement or old repaired units), this problem is yet awaiting the proper response from the Hoya Pentax!
Don't have high hope and expectation, though.. (despite that our expectation is actually very reasonable!) Has Hoya Pentax ever responded to the so infamous and well proven dead SDM cases and issue yet? EVEN after so many years of the same issue and so many complaints/loss of sales?? >:-[
Read Also:-
The State of Pentax (by Q1 2011)
Pentax Losing Momentum in Japan?
Pentax' Performance Evaluation Against Forbes' Seven Secrets of (Successful) Companies
calluses · 731 weeks ago
RiceHigh 110p · 731 weeks ago
Toomas Kadarpik · 731 weeks ago
Nubi · 731 weeks ago
gremlin · 731 weeks ago
A sensor/IR filter/AA filter is almost always a sealed unit in some way, stains under the IR filter after manufacturing should not be possible.
RiceHigh 110p · 731 weeks ago
Swidowgow Shuhbaci · 731 weeks ago
Question? Comment? Some kind of hybrid? Yes, it's a product defect that's covered by the warranty, and they are offering to repair it. Are there any other dead horses you would like to kick?
Ishai · 731 weeks ago
I have been a Pentaxian for 30 years and have more than 20 Pk prime quality lens, the Pentax K5 is the camera I have been waiting for, but with such a serious problem, I will probably stick to my Rock Solid Pentax K10 ( five years old and still going strong). If there was an alternative camera where I could use my lens, I would kiss Pentax by,by, me and many other Pentaxians are feed up with Pentax.
yelobone · 731 weeks ago
Warranty repair, how is it possible to buy a expensive DSLR and when it arrives you have to send it in for repair. ..lol who's crazy enough to do this....