The Sigma DP2 has an f2.8 lens and a 2.85cm sensor, which I think is slightly larger than the sensors in the Four Thirds system. For comparison check out the upcoming Micro Four Thirds cameras such as those from Olympus. Exciting times for photography as these cameras are starting to promise DSLR performance in a smaller lighter package. This is a nice camera. Anyone - this is on my Christmas list (I know it's only July).