I notice that heat issues with 4k recording are blamed for the delay of a rumoured a7000.
And when the first generation a7 launched, it could only record to an external device.
What I don't get is that my 1 year old cellphone records 4k content happily, and doesn't get warm at all.
Why is 4k recording harder to achieve in real cameras? Is it the large sensor itself that requires more power?
Or is perhaps the image processing units older and takes more time to develop, than the fast moving pace of mobile phones, comparing 2012 to 2014 tech?