Deleted1929
Forum Pro
Designing, developing, prototyping, testing and then implementing a manufacturing process for a large sensor is nor something I would describe with the words "just a new sensor". In addition to the sensor itself you have to develop new mainboards and possibly even support processors. This isn't even remotely trivial. It's basically the same as completely redesigning the camera from a blank page. Remember that the 645D is basically a value driven MF digital, which doesn't leave much room for frequent design refreshes.Might not be that much R&D. Just a new sensor in the same body
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StephenG