The Optio A10 saw a big improvement in performance over previous models in the series, and the S12 shares the same qualities. Startup time is a respectable two and a half seconds, and it shuts down again even more quickly. The autofocus system is nice and quick in normal conditions, giving the S12 a sustained shot-to-shot cycle time of a very fast 1.2 seconds in single shot mode, checking focus for each shot, while in continuous shooting mode it can sustain approximately 0.8 seconds per shot, although the speed is not constant. It doesn't focus between shots in continuous mode though, so this limits its usefulness for moving subjects.
As with the S10, low light focusing is a little slow, but it is accurate and reliable, with a good AF assist lamp giving it the ability to focus in the dark at a range of a couple of metres.
Image quality too is very similar to the S10. The level of fine detail is very impressive, as good as any of the more expensive 12MP compacts. I found that it did tend to under-expose slightly, but this had the effect of preserving highlight detail, especially in the case of very bright saturated colours, something which has been a problem on some high-res compacts. Lens quality is also good for an ultra-compact, although there was some barrel distortion at wide angle, as well as some corner blurring and a little chromatic aberration at the edges of the frame. As expected, image noise at higher ISO settings is more or less the same as the S10, with noise visible at 200 ISO and significant loss of detail at 400. As usual the highest settings are best avoided.
Like its predecessors the Optio S12 is a very well made and easy to use camera, with a nice simple design that continues to look good even five years after its initial launch. Although it lacks image stabilisation, it makes up for it with numerous other fun and useful features. Performance is very good and it works well in low light, making it a good choice for a night out, as well as an excellent general snapshot camera. At £150 it is very good value for money, which will only get better as the price falls.