This is an old article on the subject of AWB and other comparisons with the Pentax K7 N D90 and Canon 550d. A friend of mine in the forum has a K3 and Sony, and Canon. His opinion is that in Tungsten light the k3 has much better AWB compared to his other cameras.
Nikon D90, Canon EOS 550D & Pentax K7 Comparison Test Digital SLR Review
---------- Post added 01-26-15 at 11:59 PM ----------
Take a look at this chart comparing cameras for noise.
JPEG signal to noise ratio
The Pentax SLR does very well in this chart, beating all of the other cameras on test quite comfortably throughout the sensitivity range. The other three cameras are fairly closely matched, and are the nearest competitors to the K-3.
Raw signal to noise ratio
The K-3 also does a good job for raw format files (after conversion to TIFF). It starts off at roughly the same point as the other cameras on test, before beating them from ISO 200 - 3200, where it is overtaken slightly by the Sony Alpha 77 and the Nikon D7100.
JPEG dynamic range
In terms of dynamic range, we have another impressive performance for JPEG files. At the very lowest sensitivities (ISO 100 - 200), it is beaten by the Nikon D7100, but after that, the K-3 beats all of the other cameras in test. This is borne out by the bright and punchy images that the K-3 is capable of producing.
Raw dynamic range
Unsurprisingly, the K-3 also puts in a good performance when looking at raw format (after conversion to TIFF) files. Here again it is matched very closely with the Nikon D7100 and the Sony A77 at ISO 100, but from here onwards it beats all of the cameras in the test until it reaches ISO 12800, where the Nikon D7100 takes over, slightly.
Pentax K-3 review: Noise and dynamic range | Digital SLRs/Hybrids Review | TechRadar
---------- Post added 01-27-15 at 12:08 AM ----------
here is another ISO comparison with the K 5 and the A 77.
ISO Torture Test: Sony A77 vs Pentax K-5 - The Phoblographer