Nikon Sensors
Oct 1 (commentary)--I speculated (from Africa) that both the D3100 and D7000 sensors were solely Nikon sensors (based upon comments made to me earlier by Nikon personnel). I'm going to backtrack slightly.
First, the D3100 sensor is clearly fabbed by someone other than Sony and represents an entirely new sensor entry. Nikon's claiming it's completely their design, so I'll run with that unless someone can show me otherwise. In terms of image quality, it's pretty darned good for still work. For instance, it's clearly better than the equivalent 14mp Sony sensor (in the NEX5 I've been testing). I'll have more to say on that soon when I reveal some testing I've done, but it's definitely a modest step forward from, say, the D5000/D90 sensor. The drawback? Video sucks. The rolling shutter problem in this sensor is about as bad as I've seen in a DSLR. So panning or moving objects tend to get the "leans" and back and forth panning is like looking into a bowl of Jello during an earthquake. That's a real shame, as the D3100 was looking pretty darned good in both features and performance until I discovered that. The strange thing is that the previous Nikon-designed sensor--that for the D3s--definitely addressed rolling shutter, so perhaps the D3100 sensor designers didn't get the memo.
The D7000 sensor is almost certainly fabbed and assembled at the Sony factory. Nearly everything external about the sensor has Sony written all over it. The packing style is Sony. The wiring to the sensor internals is Sony. The specs (I've now corrected them in my charts) are downright Sony-like. Except...Nikon is claiming this, too, is a Nikon design. There do appear to be some differences in low-level specs (besides the obviously different masking, which Nikon has always done with Sony sensors). Two things in particular stand out: video differences and ADC differences. Thus, for example, one might hypothesize that Nikon used the existing Sony sensels and put their own electronics alongside. Hard to say without more evidence, and because we don't have cameras in hand yet, it's impossible to yet dissect things and try to figure out the differences, if any.
Someone asked me why Nikon would do their own 14mp sensor for one camera and hedge for the 16mp camera and sensor. One possible explanation: Nikon was hedging all along. One speculation I heard from a sensor expert I talked to is that Nikon made the decision to go all Nikon in the future, but because that's a huge undertaking of unknown outcome and could impinge on product design cycles, they hedged their bets by making the new Nikon sensors very similar in specification to what they could get with off-the-shelf Sony ones. The hypothesis goes like this: for the D3100 Nikon created production plans for both their own 14mp sensor (if it made it to their quality levels in time) and Sony's. Thus, if they failed with getting their own first DX sensor fully up to speed, they would have a reasonable fall-back position. With the D7000 the guess from the sensor expert was that there may perhaps have been as many as three 16mp sensor initiatives for the camera: Sony-only, Nikon-modified, and Nikon-only. We seem to have gotten the Nikon-modified version, which would mean that the Nikon-only one didn't clear some hurdle to production. Again, these thoughts are speculation, though they are speculation by someone close to the Japanese sensor makers.
So I stand partly corrected about the D7000 sensor. I'll continue to sleuth around and see what I can find out.