K-S1 Does not fare well in DXO tests...

http://www.dxomark.com/Reviews/Pentax-K-S1-Sensor-Review-A-flashy-new-entry-leve...

But the spread of points between the models is hardly that great...

Still a lot better than the new Canon 7D MKII.

Indeed it is Mike!

http://www.dxomark.com/Cameras/Compare/Side-by-side/Canon-EOS-7D-Mark-II-versus-...

To be fair though the new 7D wins the above for ISO, just not against pretty much anything else!
And to be fair again as I said in the original post, the difference between the three listed above is not all that significant, the D300s noisier but then it's a dinosaur! K-S1 does much better in most other departments, not Pentax's best offering but put into perspective not bad at all really ...

A pretty good argument to stick with my K5 and spend money on lenses seeing that comparison. I bet none of us could tell the difference between a table full of A3 prints from any of them.

Pretty much agree there Bill, Pentax do seem to be very good at getting as good a performance as possible out of Sony sensors...
Was going to post some more comparisons of various Sony sensors in different manufacturers bodies but the DXO Mark site has crashed due to heavy traffic! 7D MKII Users checking up on whether to send their christmas presents back most likely

As you mention and I've said before, we really do seem to have plateaued with regards to performance out of an APS-C sensor. Nowadays the supporting features are what will distinguish the models, such as wifi built in, better metering ability (but personally I think that one has actually plateaued now also personally), predictive autofocus (something Pentax simply doesn't do at all) etc

Given the comments around Pentax's ability to tune Sony sensors, I'd really like to see what they could do with a Sony FF sensor, such as the rather stunning A7s. I see that as the natural progression for high ISO ability, given the slowing of APS-C developments in this area. The K-5 is still the present low light king within Pentax isn't it? ~ seeing as we're talking DXo here.

Is it that pentax are just waiting for the new sony ff sensor that is rumored to be comming out early next year

Pentax fans would be saying that I'm sure. Any excuse as to why there isn't a FF model yet

Just checked and the current Pentax ISO leader is the K-5ii camera at 1235 points.
The FF Sony A7s for instance comes in at 3702 and the mirrorless APS-C A6000 at 1347...

Quite happy with my K-30's performance and bang for buck still looking at all of this

I'm not sure what it all means in the real world. My friend's Canon 700D never seems to have much noise in blue skies. My K30 was pretty good but my K3 doesn't seem to like blue skies much. This is a 100% crop, raw unaltered no NR, ISO 200. Comments? - would the high 1/3200 have an effect?

RAW or JPEG?

I may bite on a K-s1 soon, but if I grit my teeth perhaps I can holdout for the first K-mount with on-chip pdaf. I suspect Pentax engineers might think of offbeat uses for that like they did to track stars with SR just an odd hunch!

Didn't they file a patent recently, for just that?

http://photorumors.com/2014/08/05/the-latest-patents-from-pentax-ricoh-olympus-a...

Not really but not having an AA filter will, same goes for the Nikon D7100, and remember Canon use an awful lof of software power to smooth things out, like in the old 7D, (Think of the infamous Canon Plastic wrap), if you want noisey skies try the original Sony A77. The fancy mirror thingy in that one put it at a disadvantage there, however anecdotally the new one seems very good, though I must confess I have never picked it up!

A difference in low-light ISO of 25% = 1/3 EV and is only slightly noticeable. That makes the A7s around two stops better than the current crop of Pentax's, that in itself needs putting into perspective...
Firstly you are talking about a camera with No pixels at all, yes thats right not one! (Humor)
Secondly the perspective:

http://www.dxomark.com/Cameras/Compare/Side-by-side/Sony-A7S-versus-Nikon-D3s___...

5 years and we move on a fifth of a stop! Basically, I suspect the sensors have not really moved on substantially in that time but the processing behind them has... Stagnated, yip...
There is always talk of new tech but where is it???

Jules that also means in 5 years Pentax hasn't got close either