4K HDMI is of limited value for 1dx2 and 5D4, Prores files are only ca 10-15 % smaller then MJpeg inside Canon. mjpeg is 4:4:2 already on the CFast card. To earn something you need 4:4:4 hdmi output which is difficult due to speed. Only advantage is longer then 30 min recordings. My atoms is a...