Thom Hogan
.One curious aspect of the D3100 is the sensor. "Nikon developed" appears in the marketing materials, and the sensor is indeed not the same one as in the NEX5 (as originally speculated) in several key ways, one of which is physical size, the other pixel count. The Nikon 14mp sensor has slightly more pixel count in a slightly smaller area than the Sony. Indeed, the area is no longer what I'd call DX. The D5000, D90, and D300 have a sensor area of 23.6 x 15.8 (28.4 diagonal), while the D3100 has a sensor area of 23.1 x 15.4 (27.8 diagonal). This represents a loss of about 2% in image circle coverage needed. We're now at 1.55x crop as opposed to the old 1.52x. It's an unusual change, but the bottom line is that the Nikon and Sony 14mp sensors are indeed different in important ways. But I'll repeat: the proof is in the pudding. We need to test the new sensor on live subjects before making any useful pronouncements about it