- 2 ranges of lenses (1/ super high-end never seem before ultra bright, 2/ very compact f2.8 lenses still high end in performance but pretty affordable)
This would be almost the dumbest thing Nikon could do, and would likely ensure their relegation to Leica's status, as a niche player in the camera world, with big name cachet but little actual influence or market presence.
Outside of a few enthusiasts with more money than skill, who's going to be buying and using these 'never seen before' 'ultra-bright' lenses? Sigma's f/1.4 lenses not fast enough for you? Even then, they're often used stopped down to f/1.8-f/2 rather than wide-open. Are Nikon going to undercut Sigma? How many f/1.0-f/1.2 lenses do you think Nikon are going to be able to sell, if they end up costing three times as much as the Sigma f/1.4 equivalent (which is probably sharper, due to a less extreme design - there's a reason the Noctilux lenses are the softest of Leica's lenses, despite being the largest and most expensive)?
These are niche lenses for artsy types - niches you fill once you have all the bases covered.
Working photographers mostly live or die by their fast zooms - 24-70/2.8, 70-200/2.8, a UWA (12-24/4, 14-24/2.8, 16-35/2.8 or similar). Action photographers need the superteles - 100-400 (or similar, as backup or a secondary lens for dedication action or as a main telephoto lens for general photography), 200-400/4, 300/2.8, 400/2.8, 500/4, 600/4, 800/5.6. Wedding and portrait photographers may have one or two fast primes at favoured focal lengths for posed portraits - say, two of 35/1.4, 85/1.4, 135/1.8 or 200/2. But no-one shows up to a shoot with a bagful of fast primes, if they could even carry them. And they are unlikely to go for a super-fast f/1.0 or f/1.2 lens, when a good-quality f/1.4 lens already does the job, weighs less and costs less (Sigma).
We've seen these ultra-fast lenses before - f/0.95, f/1, etc. They're super-heavy, super-large, super-expensive and not very sharp. There's a reason no-one makes them any more, outside of a few niche lenses. Bringing them back sounds more like the wishful thinking of an artsy type than the requirements of a photographer or the calculated profit-chasing of a business executive.
- very advanced adapter with built-in AF module for full compatibility with existing F mount lenses OR second version of the body with this adaptor built-in for rigidity and ruggedness OR both (2 versions and an adaptor). My guess is both.
It would be very uneconomical to produce multiple, substantially different versions of what is essentially the same camera. They may do it for one generation, but not for the next one. It would essentially mirror Sony's A99II, which is essentially an A7r2 designed for A-mount lenses.
Also, any adapter with a PDAF module for full compatibility with current lenses would likely be prohibitively expensive - basically, you'd need to rip out the entire AF system of the D5 or D850, put it into an adapter with an inbuilt mirror and couple up a lot more things between the adapter and body than is necessary for a simple pass-through adapter (including also designing the camera to work with the adapter). Nothing like a Metabones adapter. It would also reduce sensor performance by a third to half a stop, due to the pellicle mirror required (you can't really stick a moving mirror in an adapter. And it still wouldn't be as accurate as the full on-sensor AF approach, due to the adapter's AF sensor and the imaging sensor not being in complete alignment (the reason for AF micro-adjustment on SLRs), although a pellicle mirror design would allow for sensor-based AF to be used for corrections after the adapter had done the large, fast movements. It would likely cost as much as a good lens, unless Nikon decide to subsidise it to smooth the transition process, selling the adapter at no profit, or even at a loss. Which itself has precedent - at the launch of the A7/A7r, Sony were offering Metabones adapters with each A7/A7r body sold.
- open firmware platform with full API published
Has anyone else done this?
Even the Magic Lantern crew for Canon pretty much had to hack their way in.
- full weather proof
Depends on the model (everyone will have more than one line of mirrorless cameras) and of marginal utility anyway. I recently shot the A7r3 outdoors for multiple full days in various adverse weather conditions, ranging from tropical rainstorms with 100% humidity, to heavy snow, to seaspray, and never had any issues with it. In actual use, no-one's going to be putting the camera under a shower head for 20 minutes - the photographer will give up before the camera, and you probably won't be shooting much under those conditions anyway, due to poor visibility and raindrops on the front element. If you're covering the lens to stop raindrops on the front element ruining your shot, you're probably also covering the camera, once again rendering the issue moot.
