Samuel H
Major Contributor
Well, right now, on the amazon best seller list, it's between the a7 and the a7R, so it can't be too bad, but only Sony knows if that's enough to warrant the development cost of a new sensor for the a7S II.
In terms of what they could do, you're exactly right: the a7R II in S35 mode reads all the photosites and creates a 4K image that they think is top notch. They could do the same out of a 18 Mpix FF sensor, and if they make it BSI it could mantain or improve the ISO performance. Give it in-sensor phase-detect AF, and it's a very fine stills camera too.
Now, about price, I wouldn't be nearly as optimistic...
model - launch - launch price in $ - equivalent yen at that time
a7 - oct 2013 - $1700 - 166,600 Y
a7R - oct 2013 - $2300 - 225,400 Y
a7S - may 2014 - $2500 - 255,000 Y
a7 II - nov 2014 - $1700 - 195,000 Y
a7R II - jun 2015 - $3200 - 400,000 Y
I don't see them getting any cheaper...
In terms of what they could do, you're exactly right: the a7R II in S35 mode reads all the photosites and creates a 4K image that they think is top notch. They could do the same out of a 18 Mpix FF sensor, and if they make it BSI it could mantain or improve the ISO performance. Give it in-sensor phase-detect AF, and it's a very fine stills camera too.
Now, about price, I wouldn't be nearly as optimistic...
model - launch - launch price in $ - equivalent yen at that time
a7 - oct 2013 - $1700 - 166,600 Y
a7R - oct 2013 - $2300 - 225,400 Y
a7S - may 2014 - $2500 - 255,000 Y
a7 II - nov 2014 - $1700 - 195,000 Y
a7R II - jun 2015 - $3200 - 400,000 Y
I don't see them getting any cheaper...