Everyone expects a D90 replacement in the next three months, so let's see take a look at the expectations. Nikon has had a full 24-month cycle on this design, so pretty much anything was possible. Let's try to figure out what's probable ;~):
- Sensor. Everyone I've talked to or received messages from thinks the days of 12mp are over, and that the D90 replacement will signal that. I suppose it's possible that Nikon might do 12mp again, but the only way they'd get away with that in the marketplace is if they could produce D3-like low light capabilities in a DX sensor. I say that won't happen. The 90% probability is that Nikon will introduce a 14 or 16mp DX sensor. The surprise factor here really is only the "who." Sony's 14mp sensors haven't exactly been dramatically different enough to justify moving from the existing 12mp ones. So either Sony has a sensor we haven't seen, or Nikon is going it alone. 4:1 odds: Nikon 14mp sensor. 3:1 odds: Sony 14mp or 16mp sensor. All other bets seem like longshots.
- Video. The D90 kicked off the video-enabled DSLR craze. Unfortunately, it's been lapped in almost every respect. The list of what needs to be changed is daunting: 1080 support, multiple frame rate support, higher bit rates, more manual control, better audio support, no rolling shutter artifacts, no sub-sampling artifacts. The D3s didn't tell us that Nikon really gets what's missing, as only a few of these things were addressed. But it should be clear to them now. The only question is whether they got that message in time to have the D90 replacement address all those things. 720P/24/30/60: 1:2 odds. 1080i/24/30: 3:1 odds. All other bets seem like longshots (more on that below).
- Autofocus. While there's nothing wrong with the current system, it doesn't "market well." There's a big leap from the 11-sensor D90 system to the 51-sensor D300s system. I look for this to be addressed. Expect something in between, like a 21- or 36-sensor version of the D300s system. New autofocus system: odds almost certain.
- Features. This is a tricky category. The existing D90 has a lot of features. But if the replacement only has the same feature set, a lot of people would be disappointed (not sure why, though). The question is how does Nikon appear to be extending those features without getting too far into D400 territory? I'm going to guess that we'll see more "programmability" in the D90 replacement. Even something as simple as "remembered settings" that can be triggered via a button or dial is a step forward, and falls under this category.
- Special sauce. One important aspect of the D90's success was its "special sauce" (video). No doubt the D90 would have been successful without video, but certainly less so. I expect Nikon to have noticed how important it was early on to have that advantage over their competition. So the question is what the new special sauce might be. Perhaps a built-in GPS. Perhaps Bluetooth communication to other devices. Let's hope it's not the repeat of the Ethernet connection devoted to MyPicturetown (ala the P6000)! Odds of built-in GPS: 6:1. Something else as dramatic: 10:1.
The question, of course, is whether some combination of all that is enough. For the Nikon faithful, no doubt. The minimum expectation seems to be something like this: a 14mp, better video, 21-sensor AF DSLR with a couple of "extra" features over the D90, at the same or slightly lower price point. That's probably enough, as long as the 14mp image quality is a step forward. At the upper end: 16mp, full video capabilities, 36-sensor AF DSLR with a built-in GPS (and possibly more), same price point, would almost certainly catch the interest of the current D90 user, but again, only as long as the image quality is a step forward.
Here's the kicker, though: the D90 replacement needs to live about a year with the D300s as the model just above it, and it needs to last two years in the market. Thus, Nikon won't go too far with it, I think, but has to go far enough to give it legs. If it goes too far the D300s sales suffer. Something tells me that we don't get 1080P/24/30/60 video until 2011 and the D400/D4 launches. But if it simply stays at 720P/24 that's not far enough to be competitive until 2013.
I should point out that even if a D90 replacement did appear with 1080P/24/30/60, there's still 4:2:2, higher bit rates, plus 2k and 4k video formats that a D400/D4 launch could trumpet. This brings up the important issue for Nikon: they have perpetually appeared to be "behind" Canon on most things since about the time of the D1h/D1x. More recently, the D90 video, D3 low light capabilities, and D3x image quality put them clearly ahead of Canon in a few categories. But D90-style video was an area that Nikon almost instantly fell far behind on. Nikon absolutely needs to catch up between now and the D4 launch. But will they? Canon's quick iterations in video features is not making it easy for Nikon to do so.
So, for me, the first thing I'll look at on the D90 replacement is not the megapixel count or changes to the still functions. It's the video specifications that will telegraph just how aggressive that Nikon was in development, I think.