Is it different from the EOS-1D X?
We had a chance to peer inside the EOS-1D C (No photos allowed) to find out how much it differed from the EOS-1D X. The differences are minimal, the biggest change is the heat sink inside the camera to keep the sensor circuitry cool during 4K video operation.
The EOS-1D X has some traces of the EOS-1D C firmware code and the features are locked. We don't know how much of the firmware is the same.
Third Party Firmware?
I was told by someone at Canon that they would “bring the might of its legal team” to anyone that attempts to modify at the software level, the features of an EOS-1 camera body. So I think the firmware community out there today will probably leave the EOS-1D X alone.
More to come on this topic I'm sure. I am hopeful that someone provides pictures of the inside of the EOS-1D C in direct comparison to the EOS-1D X.
Why does it cost so much more?
Production of the EOS-1D C is going to be a lot less than even the limited production EOS-1D X. Especially when you compare the numbers to the 5D Mark III or a Rebel. The software development will also add a lot of cost to the camera. How much bigger their margin is on the EOS-1D C over the EOS-1D X? I have no official word on that, but I'd love to hear about it.
Canon EOS-1D C at B&H Photo for $11,999