And you don't think Nikon would have asked for something than just a 45 MP sensor?
I suspect they asked for that sensor specifically. They’re the only user. My best guess is that Nikon flowed Sony key design characteristics, including resolution. If Nikon wanted more at that time, they could have purchased from AMS (70MP full frame), but they evidently wanted something custom.
Why is Sony the first out with a 60 MP sensor?
In a full frame camera you mean? I dunno, maybe because Sony is aggressive and Canon has not opted to cut their 250MP APS-H sensor in a larger format.
How long does it take to develop product? Most likely more than a year.
My only frame of reference is military electronics. Since this is commercial, I’d guess probably 18 months, maybe less. Sensors more like 2 years minimum.
IMX455 was announced December 2018. You must think Sony only started developing the A7R4 after that, but I don't think so.
I must? No, I must not and I don’t.
People aren't buying Sony just because of size anymore. It was their first advantage TOGETHER with sensors. GM lenses are not light. That is not why people buy Sony now.
Of course they aren’t buying
just because of size. Note the words used above. “Main reason” clearly does not exclude other reasons.
Do you know that Sony A7R4 is using IMX455 or is it using a higher version of the chip, IMX551 (from Sonyalpharumors, so take that as you will)?
I don’t think anyone knows that outside Sony. Guess: the cheaper one; they probably won’t put or be able to put sufficient processing in that form factor to make use of 551. I suspect if they package that in a camera at all, it will be in the Cinema lineup.
So you're telling me, that Sony started developing the A7R4 after December 2018 and already has it as a product.
I’m telling you nothing of the sort. What I’m saying is that I don’t believe Sony withholds sensors from Nikon.
And as far as Sony is concerned, Nikon isn't the the target competitor as it is starting to pass Nikon as the #2 manufacturer. The target is Canon, who still makes its own chips for its higher end cameras.
As far as Sony is concerned, or should be, Nikon is a great customer. It’s in their best interest that Nikon remains a viable vendor.