We had a feeling we'd be seeing the well-leaked Nikon D3100 this week after the Coolpix S1100pj and S5100 were officially launched on Tuesday, and here it is, right on cue. Just as we'd heard, the big news is the addition of a 1080p/24 H.264 AVCHD movie mode with continuous contrast-detect autofocus, complete with face detection and subject tracking. That's a major first in the DSLR world, although we're extremely curious to hear how much focus motor noise you can hear in the clips -- we've
