See:-
645D Vs K-5 Vs K-7
So, now I know that why "the K-5 is what everyone needs" and that hence there is simply no meaning of the 645D at all, as the RAW IQ is just the "same"! ;-D
And, just not to waste the remaining choice for the comparison, I selected also the K-7, which is the Pentax DSLR that scored the lowest mark as tested by the DxOLabs. The poor little K-7 really looks rather bad for this head-to-head direct comparison! :-(
Still waiting for the D7000 result, though. It would be interesting to see if the results would be more or less the same when the same sensor is used but without something in front of it that causes light loss. In the meantime, we can compare this:-
NEX-5 Vs K-5 Vs A55
Btw, just Welcome to the New King of APS-C DSLRs of the DxO BenchMark! :->
Still, for critical thinking for both sides of anything, do read this:-
Ten Reasons for Thinking Twice before Decided on a K-5..
Update (11-8): D7000's DxOMark is Out! I think the following would be the hottest comparison!
D7000 Vs K-5 Vs 60D
Well, as we can see, the results of the D7000 and K-5 are indeed very close. So, in fact, the "super IQ performance" of the K-5 is indeed a Sony achievement, but not particularly a Pentax one!
Read Also:-
K-r DxOMark and Yet Another ISO Test (Full Sized but Not Original)
K-r Vs K-x ISO Measurbations (Head to Head)
My K-r First Hands-ons (Tested Twice)
60D Vs D7000 Vs K-5: What Would You Acquire?