NR has received an email about the rumored Nikon Medium Format System. Highlights include:
"Nikon will be bringing out a middle format camera by the end of the year"
"This information has been confirmed to some pro photographers as well as Nikon distributors, camera will have a CCD size of 55×55mm, there's no exact details on final resolution yet but it will be somewhere around 50Mp, quite similar in design to that of the Leica S2 camera system which was announced six months ago."
" New lenses for the new middle format camera will be announced which will cover the larger format as well as lens specific extenders/adaptors which will allow those standard FX lenses to be used on the D4, these adaptors will convert standard FX lenses to cover larger image size such as that of D4 but will not have the true optical quality such as those designed specifically for middle format Nikon D +++ cameras to come in future."
No specifics on the lenses, other than a full range being available on release except for 35mm, 80mm and 180mm lenses along with 0.7 retro-adaptors for standard 35mm Nikon lenses.
As for price: $30.000,- to $40.000,- USD range, (Euros in Europe)
And the end with "No rumors, facts..."
They imply the D4 onwards will be medium format, and the DXXX prosumer line will be FX. I wouldn't put much weight behind this one: The Nikon D4 will almost certainly be a replacement for the Nikon D3 series, aimed at Nikon's traditional market (are they really suddenly going to ignore their mass pro market?). If the MX camera does materialize, it'll be called something else. Nikon Stuck with the F1 through F6 naming for 50 years, and D1 through D3 since the dawn of digital.
While the adapter to use FX lenses is possible (it's called a teleconverter - TC's basically enlarge the image circle, so the adapter would be a TC with a new mount), the loss of quality would surely make the lenses next to useless (the current 2.0x TC softens the image quality noticeably with current lenses, I can't image what that would look like with a mega-resolution 50Mp sensor). An Adapter that would allow you to use lenses in a "FX" crop mode would be more believable.
Source: NR on 2/12/2009.