Originally posted by Fogel70 I have not seen Sony 42 and 12 MP FF sensors used in A7 series used by other brands since they where released 2 years ago. The new 24 MP FF sensor in Sony A9 will probably not be in another brand camera for some time. The development of Sony APS-C seems to have slowed down the last few years, so I don't know if they relesed any new APS-C sensor in a while. It's usually the high end products (sensors in this case) that are most difficult to produce and will be available in limited amout during the first production runs.
Ricoh can't start developing a camera like GR-E until the have the full specification of the sensor and they know it will be available when they start to produce the first prototypes maybe 12-18 months before release. Using something new as a curved sensor will take longer to develop as there is no existing sensor the can use for prototypes. Which makes it much more likely for the sensor manufacturer to release a camera first. Because they have access to the specification and sensors much earler.
I don't think the situation is like you describe it. Sony Semiconductor has sensors that they keep exclusive for a the Sony camera division, and others commissioned by other customers. Considering the 12mp sensor, it may well be an exclusive to Sony, but who would buy it otherwise? I can't see other manufacturers breaking down the door to get a 12mp full frame sensor. As for the 42mp sensor, it appears that they did try to sell it to Nikon for the D850, but Nikon wanted a custom job. Them Hogan explains in this article.
Sensor Wars Update | DSLRBodies | Thom Hogan
Actually, that article is interesting, because it paints a picture of Sony still struggling to meet demand after the earthquake disruption and manufacturers looking for an alternative. I'm pretty sure that Sony spent a lot of last year apologizing to customers for not being able to produce their orders. With a potential new competitor, that's not a good place for them to be.
Regarding the curved sensor, it's another niche sensor. They can't sell it for DSLR cameras. They can't sell it for any existing mirrorless system. My understanding is that it's difficult to build a zoom lens to work with a curved sensor. So that leaves fixed focal length compacts. So it will probably be used in the Sony RX1 series, but beyond that the market is very limited. If they are indeed making this, it's quite possible that Ricoh has been an intended customer from the start, and even involved in the development. Also, it might be a lot cheaper to order this as a relatively simple sensor without the video tech in it.
Ultimately, I'm still not sure about this rumor at all, but the idea that they Sony Semiconductor would not share specs with a customer is not credible to me.