Look and Feel
The Q10 differentiates itself from the others with its slightly more generous assortment of physical controls dotted around the body. It's the only camera to have a mode dial, for example, and also alone in offering a hotshoe for the mounting of external accessories.
None of the three cameras offers a viewfinder of any sorts, but each camera's display has something different to recommend it. The Q10's display has very little noise when working in poorer lighting conditions, while the S1's display - while also being largely free from noise - has a very smooth feed as the camera is panned around the scene. The NEX 3N's display is a touch brighter than the others, and shows better contrast too. All three displays resolve a very similar amount of detail although, overall, the S1 edges its way to the top of the pack.
Colour and Auto White Balance
While none of the cameras' Auto White Balance systems make any serious errors of judgement, there are differences. The NEX-3N typically reproduces the scene very slightly warmer than the other two, with a subtle magenta cast over more neutral areas. The Q10's slightly inconsistent results means some images show pleasingly vibrant colours while others end up a little flat. The Nikon wins for accuracy, although some may prefer more vibrant than neutral colours.
The Q10 is the most inconsistent with its metering system, being easily swayed into both under and overexposure on occasion. In the latter case its highlights easily lose their details on account of the small, populated sensor. The NEX-3N does well in a range of conditions, with its slight tendency to underexpose from time to time easily rectified with the DRO function, while the S1 shows a similar performance, often getting it right with just the odd underexposure.
Resolution and Image Noise
With both the largest sensor and the highest pixel count, it comes as no surprise that the Sony NEX-3N maintains the best resolution across the sensitivity range out of the three cameras. The Nikon comes second with a reasonable performance at lower sensitivities and a mediocre performance at higher ones, while the Pentax Q10 comes in last place.
For all its prowess elsewhere, the S1 can't quite deliver the cleanest images at higher sensitivities. The Sony NEX-3N shows that even with a higher pixel count, the larger sensor allows it to control noise far better than the other two. Its images show more detail and better contrast than the those from the S1, and far more on both counts when placed next to the Q10's images.
When set to their Auto-area AF modes, the Nikon S1 manages to acquire focus almost instantaneously. The Q10 and the NEX-3N take just a fraction longer, with both confirming focus in roughly the same time as each other. This is most likely down to the hybrid AF system employed by the Nikon S1, which uses phase-detect AF pixels on the sensor in combination with contrast detection. The others aren't necessarily slow as such, just marginally slower by comparison. All three struggle to maintain focusing speed in low light and against low-contrast subjects, but their respective AF assist lights mean they do eventually get there.
When capturing video the Nikon manages to produce richly detailed footage, with low noise and artefacting, and reasonable sound quality. The Sony NEX-3N manages to capture a good level of detail, but it's not quite as crisp as the Nikon's video and is bothered more by artefacts over areas of fine detail. The Pentax Q10's movie mode should suffice for everyday videos, but it falls behind the others by struggling to resolve details, despite its Shake Reduction system doing well to stabilise footage.
The three also vary with their shot-to-shot times. Here the Pentax comes last, taking a surprising amount of time to process just one or two Raw+JPEG frames; this can be inconvenient if capturing a scene as it's unfolding. The Sony NEX-3N fares much better, maintaining operation as a steady stream of images is captured, while the Nikon S1 seems unwilling to slow down between captures, writing them quickly to the card.
So, with its excellent AF system and super-fast burst rates the Nikon S1 is clearly the best option when action presents itself. The Sony NEX-3N's wider kit lens and articulated screen is more suited to cityscapes and landscapes, and a good candidate for reportage, while the Q10's is best suited to those who require the full control of a DSLR in the form of physical controls, and system expandability offered by the hotshoe.