One of the admittedly small number of things that differentiates the DP2s from the DP2 is supposedly faster focusing and image processing, but the overall performance is far from sparkling. In single shot mode the shot-to-shot time is approximately 2.7 seconds, which is quite slow by the standards of other high-spec compacts, but in its favour it will shoot at this speed in both JPEG and Raw modes. In continuous shooting mode it can manage just over two frames a second, but only for a limited burst of four shots in JPEG mode and three in Raw.
The autofocus is very slow, and is also extremely noisy, with a loud mechanical whirring sound as it cranks the lens into focus. Low light focusing is the worst I've seen in several years, with the camera failing to focus in a room lit with a 60 watt bulb. It has no AF assist lamp, so once the light level drops you have to switch to manual focus.
One area that does seem to have been significantly improved over the previous model is battery duration. Joanne said that she only got about 50 shots out of the DP2, but I was able to take over 200 with the DP2s, which is powered by a chunky 1300mAh lithium-ion battery.
Fortunately the DP2s does have one saving grace that trumps all of its shortcomings, and that is its simply fantastic image quality. At 50-200 ISO it produces a level of detail, dynamic range and colour depth that easily surpasses any other compact on the market, and even puts some mid-range DSLRs to shame. There is no trace of image noise at 200 ISO, and even at 400 and the maximum 800 ISO noise is slight, even and grain-like. The lens too is superb, with brilliant corner-to-corner sharpness that makes the most of that fantastic Foveon sensor. The control over depth of field provided by the wide maximum aperture and large sensor allow real creative control for portrait shots.
The Sigma DP2s is a well-made camera, although the blocky design and primitive control layout look very dated. Handling is average at best, and the slow and noisy performance and terrible low-light focusing might put off the casual user, assuming that the terrifying price hadn't already sent them running back to the the safety of a consumer compact. However if you're prepared to put up with its flaws it rewards you with spectacular image quality and photographic versatility that beat any other compact hands down.