Funny thing about HD camcorders using 10-megapixel (or bigger) sensors. Most of those pixels are wasted when you're shooting 1080p video. So Canon's new HD CMOS Pro sensor is just 2 megapixels. With gianter pixels, more like a studio camera.
Bigger pixels usually means awesomer low-light performance and dynamic range. The HD CMOS Pro sensor's pixels are 2.75 microns, to be precise—which is still smaller than 6.4-micron pixels in Canon's 5D Mark II image sensor—but not too shabby.