From NikonRumors:
"The Nikon Z6 III is rumored to have a stacked sensor (or partially stacked?) from Sony. That same sensor is expected to be used in the upcoming Sony a7S IV, rumored to be announced later this year. I was told that Nikon got a special and exclusive contract with Sony and only Nikon and Sony will use this specific sensor. Nikon had to buy a lot of them in order for Sony to agree on exclusivity. This explains the rumored high price of the Z6 III."
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