The three pocket-sized cameras are among the best in their category. Their biggest problem today is that the sensor is compact-sized, too. The more noticeable improvements between the previous and the newest models (G11 compared to G12 and P6000 to P7000) concern mostly the layout and the handling of the device more than the image quality itself.
The newly-launched mirrorless bodies, with their much bigger sensors, provide much better results than these cameras with smaller sensors. This is true for almost all measurable areas, and especially as you increase ISO sensitivity. Moreover, a bigger sensor allows both a higher pixel count (usually 14 megapixels for a mirrorless APS-C) and a pixel pitch two times larger.
Let’s look at how a Samsung NX10 with its APS-C sensor behaves compared to a Canon Powershot G12. Both cameras are in the same price range; the NX10 is a little bit bulkier.
Let’s start with the SNR value analysis because it gives good insight into image quality. Less noise means a better picture. In this respect, the bigger sensor of the NX10 does a better job, being almost 5 dB above that of the G12 no matter the ISO setting. To better understand this result, keep in mind that the SNR value given in dB is algorithmic. Increasing it by 6dB results means doubling the amount of noise (equal to 2 stops of ISO sensitivity). The NX10 APS-C sensor produces only about half the noise as the G12 at any ISO setting.
Dynamic range, too, is clearly a domain in which the bigger NX10 sensor performs well, although the G12 still shows very good results below 150 ISO. But if you increase sensitivity, once again the APS-C rules.
Let’s finish this short comparison with the color sensitivity chart. Here again, no surprise: the NX10 APS-C sensor outperforms the smaller G12 sensor. The most interesting point is that this superiority increases with ISO: from 0.5 bit at lower sensitivities, it climbs above 1 bit at the end of the range.