Quote Originally Posted by Kayaker72 View Post
...the max ISO 6400 rumor probably stands out most other than the 53 MP. I am not sure what it means yet. I am hopeful that Canon is breaking with their past and the max ISO is actually usable. It actually doesn't make sense to me otherwise. The 7DII has a max ISO of 16000. The rumored 5Ds has the essentially the same pixel density. Why would ISO go backwards in ISO performance with the same pixel density? The closest answer I have seen to this is that they are enhancing the bayer filter to get better color rendition. But that costing 1.3 stops of light? Also, there has been talk/rumors of Canon finally putting their analog/digital converters on chip rather than off, which is supposed to reduce the noise.
Just a little mussing... nothing technically researched, but:
Given the much higher pixel count over the 7DII, I would assume there is more heat generated (creating more noise) which may also limit the usable ISO. Yes, it has more surface area to lose heat, but I would assume the heat generation is at a greater rate that the cooling rate. My simplistic analogy: Stick 20 people in a 10'X10" room and it is going to get stuffy... put 50 people in a 16'X16' room and it is going to to get hot (and unbearable). So unless they add active cooling to the sensor, then I would assume the noise would go up.

Pat