The Q10 is the second iteration of the series, being a more value-priced proposition than the original Q, largely by replacing the magnesium shell of the original with a plastic one. It debuted in September of 2012 and featured a 12MP 1/2.3" sensor...
A digression to mention that digital camera sensor size descriptions date back to the earliest days of digital video. A 1/2.3" sensor is 6.17mm across by 4.55mm tall, or 7.66mm across the diagonal.
The Nikon, which hit the market in January of 2013, has a sensor with the same physical dimensions, but 16MP resolution. The lens on the Coolpix is the equivalent of a 25-300mm zoom, in 35mm terms, but only an f/3.1-6.5. Consequently the Coolpix tends to be noisy at longer focal lengths in anything but the best of lighting conditions.
With a wider choice of bigger, specialized lenses, and the ability to shoot in RAW for better image processing, the Pentax Q10 ekes a lot of performance out of the little 1/2.3" sensor by comparison...but it's still a tiny sensor. Noise is going to happen at higher ISOs no matter what trickery you employ.
