The overall results obtained by the two Pentax digital reflexes are very close, with only 3 points’ difference in favor of the expert model K-5 — a lead of only 1/3EV. Although the color depth is absolutely identical for the two cameras and the low-light sensitivity is in the same general ballpark, we nonetheless note a real difference in dynamic range between the two cameras: only 13EV for the K-30 (the same as for the K-01, Pentax’s compact hybrid equipped with the same sensor) versus 14.1EV for the K-5 (the champion in this category). The K-5 has the advantage of an 80 ISO setting that lets it improve its dynamic range score, and gives it slightly better control of shadows than the K-30 (this said, a difference in dynamic range of only 0.7EV at 100 ISO will be difficult to detect in photos).
With a DxOMark Score of 79, the K-30 marks a tangible advance over the K-x, Pentax’s entry-level reflex, which scored a total of 72 points during its passage through the testing process. The difference translates into a qualitative gain of a little more than one third of a stop. The color depth of the new reflex is better than the entry-level model by about a bit, and the dynamic range is only a half-stop better because the K-30 doesn’t take full advantage of the dynamic range usually found for this sensor. But it’s the K-30’s low-light sensitivity that is its most important advantage over the entry-level K-x: more than 1/3 stop, 1129 ISO vs 811 ISO.
Even though the Nikon D3200 is not as tropicalized as the Pentax K-30, we know that the Nikon’s 24 Mpix CMOS sensor will be used in other cameras slated to appear in the coming months, just as it is already being used in the Sony NEX-7 and SLT-A77.
The overall image quality measured for the two cameras is very similar, giving only a very tenuous 2-point advantage to the 24-Mpix sensor, which benefits from a color depth score of 24.1 bits versus 23.7 bits for the 16-Mpix CMOS sensor. In terms of sensitivity, the score for both sensors is equivalent, even though when viewed on a screen, a photo taken at high sensitivity with the Pentax will be more flattering (this advantage disappears on an A4 print).
Note how the Pentax’s signal-to-noise ratio takes a jump at 1600 ISO and higher when compared to the D3200.
DxOMark Score: With a DxOMark Score of 65 vs 79, the 18Mpix APS-C sensor of the Canon digital reflex shows a performance gap with respect to the Pentax. This gap is in evidence across all image quality performance criteria. Of particular note is how the gap widens for the “studio” scores in which we evaluate sensor quality at low ISO.
Color depth: 22.1 bits vs 23.7 bits in favor of the Pentax — and this difference is important when comparing two cameras of the same generation.
Dynamic range: 1.5EV separates the cameras in favor, once again, of the Pentax. We know that the Canon CMOS is not very generous when it comes to dynamic range — and in fact, it makes no progress in this regard after 400 ISO, in contrast to the behavior of the K-30, which itself is not the best in this category in the Pentax line.
Low-light sensitivity: The Pentax achieves a score that is ½ EV superior than the Canon. As one can very clearly see on the SNR curves measured at different sensitivities, the Pentax is relatively close to the Canon EOS 600D up to 1600 ISO. 1600 ISO happens to be the last sensitivity at which the two cameras evolve within the same world, because starting at 3200 ISO, the Pentax applies smoothing that softens the image and limits noise — but at the expense of sharpness.