Last time, it was reported that scratches were found by different users of the K-5 on the "sensor" of their brand new units. Until recently, different people found that the AA (Anti-Aliasing) filter, which is on the top of the sensor and actually covers it, is different from that of the Nikon D7000, which shares the same (Sony 16MP) sensor.
However, the reports of the same scratched sensor issue continue, more and more new K-5 users have reported the issue and evidences are shown, two example threads below, note that there are multiple users reported the issue per thread:-
http://forum.xitek.com/showthread.php?threadid=811347
(Simplified Chinese, machine-translated English page here)
http://forum.xitek.com/showthread.php?threadid=803669
(Simplified Chinese, machine-translated English page here)
So, possibly Pentax bought the Sony sensors but made their own AA filters. But once again, the quality control of them is not good so that some of the AA filters they made do contain defects but unfortunately those defective items were still put into the new K-5 units which were shipped ultimately without being caught by the final QC process, if any. This could explain why it has never heard about similar case of any for the Nikon D7000, but only about the K-5.
Besides, as for that super-strong blur filter, some people would argue that it is a design feature of the K-5, but then how about those scratched AA filters? :-o It is not even to mention that the too-strong AA filter does decrease too much the image resolution but just causing obvious blur and ridiculous softness, which has also been repeated proven from all those new K-5 samples that we have seen up till now! :-( In fact, I have seen a K10D user whom has "upgraded" complained about that his new K-5 is not as sharp as his old K10, so?
Last but not least, if you are just one of the unlucky new K-5 users, just all the good lucks to you as very possibly Hoya/Pentax would never admit the problem but on the other hand the service quality and after-sales support (if any) are always impressive, but on the negative side!
In fact, as we can see from the case of the first reported K-5 user who found the issue, he only managed to get a replacement unit after struggling for weeks but then now his "new" K-5 replacement is yet still defective with another problem! Oh, well.. >:-[
Last Related and Must Read :-D
Ten Reasons for Thinking Twice before Decided on a K-5..