The D7000 announcement has triggered a huge swell of emails with a question that was already on a lot of minds: will there be a D400? And if there is, what will it be like?
The first question is easy to answer: yes. Simply put, Nikon isn't going to have a US$1800 gap between the D7000 and the D700 replacement when it eventually comes. That's actually a bad place for Nikon to have a gap, as that's the one place that has been an anchor for Nikon's DSLR success. The D90 and D300 were profit machines for Nikon, and clearly distinguished Nikon from Canon in the serious amateur and prosumer market.
The better question to ask is this: will there be a D90 replacement? After all, Nikon has said that the D7000 is not a D90 replacement. Many people have interpreted that as the D90 will stay in the lineup for awhile, then go away. But what if there really is a D90 replacement coming, too?
What seems like a really long time ago, I wrote in a newsletter that I thought that both Canon and Nikon would add models to their DSLR lineup. At the time, I think both had five models, and I was guessing they would extend to six or seven. At present, Nikon has nine (D3000, D3100, D5000, D90, D7000, D300s, D700, D3s, D3x)! In that context, those of you worried that the D300 line will go away are hypothesizing that Nikon will have only five DSLRs in their lineup (D3100, D5100, D7000, D800, D4), or maybe six (D4h and D4x instead of single D4). No, Nikon won't go so far backward to have only five DSLRs, as that would cause some serious price gaps to open up and allow competitors to "split the difference" on them.
My guess is that Nikon's lineup by the end of 2011 will be at least this deep: EVIL, D3100, D5100/D6000, D7000, D400, D700x/D800, D4. The D5100/D6000 and D700x/D800 naming confusion depends upon when the new models arrive. Once the D4 is out, all models should start with an even number again. Until then, we're in the odd number generation. (Yes, Nikon is that precise about naming. Apparently marketing doesn't get a say in names.)
So if I'm right, what would a D400 look like? Well, to fit into the price gap it will have to be DX, I think. I know of nothing that really allows the camera makers to get healthy product margins on FX bodies at the expected D400 price point. To be differentiated from the D7000, a D400 would have to have a feature set that is compelling beyond the D7000. That means 8 fps minimum, either an integrated vertical grip or a better optional grip system (think F4s), better focus system (from the D4), stereo sound, and more. I don't think it needs more than 16mp, so it could probably use the sensor from the D7000, only faster at data transfer (for that 8 fps+). Frankly, that's enough--especially if the focus system is the D4's rumored one. And such a camera would immediately become a wildlife photographer's favorite, I think.
Short answer: there will likely be a D400, and it should be an impressive camera. I could have used one in Africa last month ;~).