http://forums.dpreview.com/forums/read.asp?forum=1036&message=37092371 (Part 1)
As the discussion quickly reached the 150 posts upper limit for less than 24 hours, he has opened another part for further discussions:-
http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=37101106 (Part 2)
Besides, see also what is quoted from a K-5 user for what he has been made known from the Hong Kong Pentax sole agent:-
http://www.dchome.net/viewthread.php?tid=949406&page=25#pid11318050, quoted:-
"According to Jebsen,
The spot was actually appeared on the back of the CMOS,
Not at the front ......"
So, the "stains" and spots are actually underneath the AA filter, not above it. So, this must be a manufacturing defect, undoubtedly. But on the other hand if the most unfortunate user has the stains above it, i.e., in front of the AA filter, would Pentax still admit the problem and give him/her a replacement? :-o
Update: Lately, near the end of the "Part 2" DPR discussion thread above (at the time of updating this post), we see these evidence photos, which confirms what is told above, i.e., stains underneath AA filter:-



Then, the user will get such an image, when taken with that defective K-5 with smaller apertures:-

Previous Related:-
Nice Summary and Suggestions on the Scratched K-5 "Sensor" Reported Cases
Scratched "Sensor" Cases of the K-5 Units - Quality Issue of the AA Filters Manufactured by Pentax?
Scratched Sensors of Brand New K-5 Units
Ben · 744 weeks ago
illdefined · 744 weeks ago
too bad you only update negative posts and not the ones proven wrong.
ArcticExposure 45p · 744 weeks ago
Btw, it's not "flagship", it's just flagship, as that's what the K-5 is for Pentax ;)
Peter Fang · 744 weeks ago
Thanks for mentioning my threads and let's do not make our own assumptions and discuss this in a civilized way. :)
Peter
rhermans · 744 weeks ago
Seriously this should be replaced, and I don't think that any repair would deny that the way it's documented.
But as with all helpdesk/repair/service stations now to make them understand that you do know what you're talking about.
Hopefully this will be the only where they have the problem.
Ben · 744 weeks ago
It is simply not smart for Pentax to hide and not say anything. Lets hope it will. This is so obvious a problem it should fix. If it continues its old way and do nothing, then it has no future. It is not just about sensor stains, or SDM, or shutter blur or whatever problem. It is about how its treats its customers and how much it can be trusted.
Isn't Internet wonderful. Thanks, Rice for this publicising this.
jviviano · 744 weeks ago
Good find, Rice, but the spin is a bit aggressive. I would suggest you reserve the harshest commentary for reports that Pentax would not replace these defective sensors.... which I really doubt they would do.
Ben · 744 weeks ago
I think you should update your Tens Reason To Think Twice ... with a new 11th reason, the most important of all, and that is this matter of ethics and trust in a company. It is not just about SDM, that lack of FF, lenses, this or that problem in flash, a QC or a design any more. All those problems are partly the result of what a company stands for and how it treats its customers, especially when there are issues. You should think twice before buying from a company that you do not believe will do the right thing and look after you.
OGL · 744 weeks ago
the same problems were with Canon
OGL · 744 weeks ago
Eddie · 744 weeks ago
OZDean · 744 weeks ago
This is mad!
David · 744 weeks ago
David