Hi,
You make a lot of statements with very little substance behind.
If you check the Pentax 645Z, it has 8256 x 6192 pixels, that is 8256 columns and 6192 rows. Full frame 8K would need around 8k rows but normal 8K would need 4320K rows. That said, the sensor could be useful for 4K, sampling a complete RGBG quartet of pixels for each pixel on screen.
In cinematography full frame essentially is very close to APS-C, so Cinema lenses are not developed to cover larger than that, and absolutely not for medium format sensors. Again, 8K may be a different thing, with new lenses and all…
My guess is Sony is making those sensors for MFD cameras, and some special applications.
There is a reason to talk Sony, as that company is dominating the CMOS sensor market, having a market share of about 42%. The remaining 58% is split among smaller firms. Also, Sony is making the only CMOS sensor used MFD cameras, except the one in the Leica S (Type 007). So Pentax 645Z, Phase One, Leaf and Hasselblad are using a 44x33 mm size 50 MP sensor, and Leica is using a 45x30 mm size 37.5 MP sensor.
As far as I know all companies are quite tight lipped about coming developments, but it is assumed that Phase will release 100+ MP sensors sooner or lighter. Reasonably that may be CCDs from DALSA at full frame 645, or CMOS, Sony would be a good candidate for that.
With Canon, Sony and in all probability also Nikon moving into the 40-54 MP resolution business, I would guess that MFD needs to move upscale in resolution. Zeiss is developing some new lenses for those new generation of sensors, two of the Milvus lenses are new constructions and that applies to the new Otus 28 and the Loxia 21/2.8. In addition Zeiss makes the Batis lenses for the Sony. Canon quietly revamped their lens program with generation LII lenses and they also revamped their focusing systems. So, there are a lot of decent quality lenses for 50 MP (or so) on 24x36.
All MFD makers except Leica use larger size sensors sporting less rectangular formats. I also think that Leica keeps their own sensor and doesn't sell to other makers. Also, it seems that Leica is not interested in larger format or more megapixels.
Just to make some small point. Would you know anything about things you would be under one or several NDAs. So you obviously speculate. Those who know are not allowed to tell.
Best regards
Erik
I believe what you people are missing, is that the Sony (current 51mp) sensor is in reality a motion picture sensor aimed for 8K cinema (8192 rows needed)... Therefore, Sony won't consider another cinema large sensor.... There are larger Cmos sensors in production currently (all made for cinema) that are exclusive to motion picture hardware makers... The access to these sensors is very difficult as they are under contract from the makers they are exclusively made for and because the MF market is peanuts in comparison as to add something worthwhile in production to consider... Therefore, one should expect only a "friendly" MF maker to have access to the ...charity! Now, Leica seems to have find a supplier, Hasselblad is already providing lenses for Arri 65 (one of the right owners of large format sensors) and if one additionally considers their recent collaboration with other motion picture companies, they seem to have direct access to larger than Sony's sensor solutions (their recent pricing policy where they are moving the Sony sensor as to be their entry product, thus leaving the field open for "larger" is a proof).
One thing is for sure though... if a sensor will be "wide open" to all MF makers, that will be a Sony sensor (which there already is...). All other (future) sensors will be exclussive to one MF maker only... It won't be accessible by the rest of the makers...