While we did note an improvement of just under 1 Ev in our Sports (Low-Light ISO) score from ISO 117 to ISO 216, no doubt due to the improved light-sensitive capabilities of the BSI architecture the XZ-2, there were also significant improvements seen at low ISOs. There’s nearly a 1.0 Ev improvement in the Landscape (Dynamic Range) and more at higher ISOs as well as over 1.5 Ev in Portrait (Color Depth) use case scores. The 11.3 Ev Dynamic Range is very good for a compact and better than some 1-inch sensors, such as that found in the Nikon 1 J3, but the Low-light scores continue to be well behind modern DSLRs, as you might expect.
The Canon has a tempting spec, including a similar resolution sensor and lens ‘speed’ but with slightly longer zoom range from 28-140mm (the longer focal lengths accounting for f/2.8 max aperture at 140mm). It also image stabilization, sensitivity up to ISO12,800 and has a built-in (albeit small) optical viewfinder.
However, while the Olympus sensor performs similarly in general terms it should potentially be more suited to portraits with its higher Color Depth (equating to around 0.5 stop more) than the Canon G15, though in real world use the differences are too low to be obvious in images.
Compared with the Nikon, the XZ-2 can’t quite match it in Color Depth or Dynamic Range. Qualitatively, the improvements in image quality wouldn't be noticeable and that's also likely true in the Low-Light ISO scores, where the Olympus is ahead slightly. You might see performance differences between the Canon and Nikon but the XZ-2 sits in the middle of those two in terms of the quality of sensor output.
The Nikon, however, is a very strong challenger. Not only does it have the longest zoom range, equivalent to 28-200mm, only a slightly ‘slower’ f/2.0-4.0 maximum variable aperture, and useful articulated 3-inch rear screen but, with a DxOMark score of 53, it performs very well indeed. It’s also about $50 cheaper. It’s also worth noting the decision to drop the optical finder of previous iterations may be a shortcoming for some users, especially as there’s no option to add an electronic finder. The Olympus has a choice of two models, both originally designed for their micro 4:3 bodies but no less compatible with the XZ-2.
Another contender in this category is the recently tested Panasonic Lumix DMC-LX7. Although it has a slightly lower 10-Mpix resolution CMOS sensor it’s more accessibly priced at around $450. It is also built around a high-grade Leica-branded zoom lens, equivalent to a 24-90mm f1.4-2.3. Not only is it theoretically, two-thirds of stop ‘faster’, the wider field of view at 24mm is a particularly attractive feature for interiors, landscapes and architecture. In our labs, the Lumix DMC-LX7 tested similarly to the Olympus with an overall DxOMark score of 50 vs 49, respectively. Most of the gains, which were slight, were made in Color Depth and Dynamic Range although with around 0.5 Ev advantage, the Olympus sensor is the better of the two in low–light.