Originally posted by Theov39 As I am interested in getting the K-3 (currently have a K-7), in what ways is the image IQ better on the K-5? Might reconsider my options if that is the case.
Honestly having had both... If you know your technique, the K5 is the inferior camera in all aspects, including low light, the area where K3 is often said to be bad. The K3 is night and day difference for AF (in particular in low light where K5 is terrible), sharpness (you have much more possibilities to crop for wildlife as an example), overall reactivity, the flash system bug from K5 is solved, the metering and white balance are more accurate. All lenses AF, faster, including screw drive thanks to the faster motor.
Beware also to not mess up K5 and K5-IIs. The K5-IIs has already much improved sharpness than to the lack of low pass filter and also an AF that may not be that great but that work in low light.
In the APSC lineup the K3 (or K3-II that is basically the same camera) is the second best overall camera after the KP... And even, the KP mostly beat it in usability (lighter, better controls) and the improved sensor. For all the rest, the K3 is as good or better (1/8000 shutter, better autonomy, 2 SD cards...).
But it is true that the K5 apply lot of blur to the images at high iso that remove the noise and people often take the mistake to see their photos at 100% for details and obviously a a K3 with 24MP show a more magnified view with more noise (and also more details overall). But if you print or look at full screen, the K3 is quite capable.
My experience with K3 in low light vs K5 is that K3 can make sharp image. K5 can't. K3 AF is reliable in low light. K5 is not. K3 doesn't apply much noise removal and as such it need a raw editor with nice removal algorithms to shine. Latest lightroom would do the job but DxO with prime truely shine.
Few example of K3 high iso perf:
iso 8000
iso 2000
iso 1600
iso 3200
iso 6400
If you want to upgrade in APSC, the best offering in Pentax is the KP then K3.