The puzzle with Nikon recently has been "where is it?" As in "where are the lenses?", where is the inventory?", "where are the new cameras?", "where is the video?".
Some of the pieces are coming into place now, particularly on those last two questions. Some cameras weren't here quite when expected because Nikon has apparently moved to producing their own sensors. The video wasn't quite all there because Nikon hadn't yet moved to producing their own sensors. The year-long gap between the D3000/D300s and D3100 was the longest DX body announcement gap we've had since Nikon started iterating faster with the D70s back in 2005. And I suspect that the gap was as long as it was because of the shift in sensor use.
That the D90 replacement is due next month and now likely to also have a new sensor in it would tend to signal to me that Nikon thinks that they've "made the transition." At this point, Nikon appears to have two sensors in production (D3s and D3100) and possibly a third is now entering production (D90 replacement). In the coming year one would expect a D700 replacement and a D4 sensor to also get added to the mix. If the D5000 and D300s get updated, they're likely to use one of the first two DX sensors that exist at the time (e.g. the D90 replacement sensor). So by the end of 2011 we can imagine all Nikon DSLRs using Nikon sensors, and there being either four or five such sensors in production. If I'm right about this, that represents an aggressive move by Nikon.
Taking this further, an eventual D4x could be somewhere around 38mp using Nikon's smallest sensel design, a figure that starts to exceed what most lenses can resolve.
Still, those of you who have read the full series of articles I've been writing about sensor possibilities in the past months know that there's one really perplexing puzzle piece: the D3s sensor. Nothing Nikon is currently working is likely to achieve the same levels of low-light performance that the D3s does. As I wrote earlier, if Nikon could product such a sensor with more pixels, it would indicate another D3 level breakthrough when none is expected. No photographer I know of wants the D3s sensor to die off. We all want it available in a future body as well as the current one. But that's the puzzle piece I can't figure out. Other than possibly making a D700s, there's no clear scenario I can see that would have the D3s sensor live past the D4 introduction. So our puzzle is not yet solved.
Meanwhile, the D3100 also introduced Expeed 2, and not a lot of people have been asking questions about that. My guess? The 2 in Expeed 2 is mostly centered around H.264 compression and other video needs. The question is how far Nikon took that. The 1080P/24 in the D3100 isn't enough for the pro ranks. Hopefully they've thought this through and are prepared to go at least as far as 1080P/60 plus 4.2.2 color with EXPEED 2. But one would really hope that a D4 would be 2k or 4k video, which would require even more from that EXPEED chip.
The puzzle is still missing pieces, obviously, but it's clear now that Nikon is pushing further into controlling the core of their imaging engine. Good for them. And so far, good for us users, too. Just don't let that great D3s sensor die off, Nikon.