Those anxiously awaiting a full frame Nikon mirrorless camera will be interested to hear this major piece of news: the company will likely be introducing a new mount, the Z Mount, for their upcoming mirrorless camera.
Here's the basic problem Canon and Nikon are facing right now: the flange distance of a DSLR is much greater than that of a mirrorless camera (for example, the EF mount is 44mm, while the Sony E mount is 18mm). When a lens is adapted to another system, the flange distance of the system the lens was originally made for must be greater than that of the adapted system to maintain the full range of focus. That's why Sony cameras can adapt so many lenses, as their short flange distance leaves plenty of room for an adapter to fill in the remaining space for the flange distance of whatever lens you're mounting. DSLRs have longer flange distances because they need space for the mirror.
Thus, Canon and Nikon are left with a paradox of how to create a mirrorless camera that isn't the size of a DSLR. Both manufacturers have an advantage over Sony, Fuji, and the like in that they have deep libraries of lenses, and if they can make those work natively on a mirrorless camera, they stand to have a huge advantage out of the gate. The other option is to create an adapter, and perhaps a first-party adapter will have less autofocus issues than a third-party one. I personally think the size advantage of mirrorless is overplayed a bit (though the other benefits are great), particularly since the physics of lens design place a limit on things. Nonetheless, Nikon Rumors is reporting that Nikon's upcoming full-frame mirrorless camera will have a new mount, the Z mount (that name could change), with a flange distance of 16mm. This would leave about 30.5mm of room for an F mount adapter (plenty of space), but it would mean that Nikon would likely be introducing a new range of lenses for their mirrorless line, and it of course remains to be seen what kind of performance adapted lenses would give on such a system.
[via Nikon Rumors]