Apparently even the crew in Tokyo has decided that Nikon has been too quiet. With only only one announcement so far in 2018—the 180-400mm f/4E lens—and no camera announcement since the D850 late last summer, Nikon has finally made another product announcement.
Only it's not a product launch, it's a "development announcement."
Nikon has used this technique of pre-announcing an announcement a number of times over the years, including most recently last year with the D850. The range of time from the development announcement to the actual announcement of a product has ranged from one month to eight months in the past, with the median three months.
Why Nikon thinks they have to do this, I have no idea. Perhaps the marketing department was just tired of waiting for something to write a press release about. But functionally, these development announcements serve almost no purpose. It's not that Nikon is trying to "be there first" or throw shade on another company's announcement (e.g. FUD). It's not that there is an expectation for the product being developed (in every case I can think of to date).
I suspect it's Nikon's awkward way of "trying to go viral." Rather than leak a rumor somewhere, they just come out an say "we're working on X." But why? No one knows. And why announce today? Completely unclear. (One possibility is that Nikon is worried that a lens or lenses being tested out in the wild will be outed, I suppose.)
What product has Nikon announced they're developing this time? Well it has an official name: AF-Nikkor 500mm f/5.6E PF ED VR. But it has very little other detail ("final specifications and pricing...will be announce later this year").
This new lens will be the 500mm brother of the 300mm PF. By using a phase fresnel (PF) lens element, this simplifies the optical path, making the lens far shorter and significantly lighter than a 500mm f/5.6 lens designed normally. But Nikon offers no details here.
We do have existing patents on 400mm f/5.6 PF, 500mm f/5.6 PF, and 600mm f/5.6 PF lenses from Nikon. The 500mm f/5.6 one features 18 or 19 elements. Total length of it was about 280mm. The current 500mm f/4 is 387mm in length, by comparison.
I'd expect the 500mm f/5.6 PF to be close to the size of the 200-500mm f/5.6E (270mm) and lower in weight (<5 pounds [2.3kg]). How much lower is the question.
And so Nikon faithful continue to sit and wait. Now at least there's something known that they're waiting for...
