If it is the NEX-7 sensor as rumoured than it should be 24MP I think. 24 x 1.5 = 36MP.
Use similar triangle pricinple, area is related to square of length. D7000 sensor at 16 MP x 1.5 square = 36.45 MP. In the same ball park ast 38 MP.
does anyone have any idea what would be the estimated mp in DX mode? For me I would love to use it with 10.5 fisheye.
Should be equal to D7000, i.e. 16 MP in DX crop.
Basis of my comparison.
Take the D7000 sensor size 23.6 x 15.6 mm = 368.16 mm2 for 16.2 million effective pixels
Take the FX sensor size 36 x 23.9 mm = 860.4 mm2
Take the ratio of the area to work out the effective MP of FX camera using D7000 sensor = 860.4 * 16.2/368.16 = 37.9 MP.
Double check, use data for D300s
FX camera using D300s sensor = 860.4 * 12/368.16 = 28 MP. D3x is 24.5 mp, so the computation is in the right ball park.
My take is, therefore, using the same wafer that is used to make D7000 sensor and build FX sensor and get FX (aka rumoured D800).
So, noise performance should be similar to D7000, i.e. not in D700 much less D3s territory. Double check - D3x noise performance is not in D700 territory, IIRC it is slightly better than D300s.