Originally posted by ChristianRock The resolution is 5472x3648 as you said. The sensor is 23.5x15.6 - all of this is from the Ricoh Japan site. These match the Samsung sensor exactly.
All media I could find on the Sony sensor says the resolution is 5456 x 3632 and the sensor size is 23.2 x 15.4 mm according to dpreview.
It's not unusual, though, for the same sensor to produce slightly different-sized images, when used in different brand cameras. And two individuals who have had some connection to Pentax in the past have declared that the sensor used was made by Sony.
But you might be right, and the sensor is Samsung - and you have provided some support for your theory. What caught my eye was in your OP where you stated, "K-S1 and K-S2 use the Samsung 20.3MP sensor that debuted in 2011 with the NX200". I think the DXOMark comparison I posted does a good job demonstrating that
that sensor was not likely used by Pentax, given its poor high-ISO performance. I guess the next step would be to compare the K-S1 sensor with the Samsung NX30.
I did briefly own the K-S2, K-70, K-01, and K-3 II simultaneously. IMO the K-S2 and K-70 had very similar color performance, while the K-01 and K-3 II were a bit different.
Interestingly, the 20MP sensor in my Panasonic G9 reminds me greatly of the K-S2/K-70 in terms of color, although I've yet to photograph a human with it.