Last Friday I was shooting some interviews in 4K with our Sony a7Rii and ran into what is probably the number one issue people are having with this camera. Overheating. After about 20 minutes of continuous shooting the camera gave me a warning that it was overheating and it shut down. The good news is that I do not loose the footage I was in the middle of shooting, it got written to the card before the camera turned off. The bad news is that I had to halt the interview and wait for the camera to cool down to start shooting (about 5-10 minutes). Battery consumption was also high, I think I managed about 40 minutes total on a fully charged battery.
Both of the a7Rii overheating and battery life issues raised some serious questions for me about the practical viability of the camera as a B-Cam in interview or live recording situations. Even if overheating were not an issue, the camera is capped at 29 minutes and 59 seconds of continuous recording due to import tax law. Fortunately there is an easy and affordable solution. A 4K external recorder.
I was curious so I hooked our a7Rii to a Convergent Design Odyssey 7Q to see if the camera would overheat. After 41 minutes of continuous recording there was no overheating issue and only used about 40% of the cameras battery. Conservatively speaking you are looking at 90 to 100 minutes of continuous recording assuming you have the media for it.
The best news of all is that the number of 4K compatible recorders on the market is growing. The Convergent Design Odyssey 7Q+ is a great choice with lots of options for high speed recording and will also record RAW output from most cameras when purchased with the RAW codec bundle. There are also 3 new 4K recorders from Video Devices that are coming out later this year and have full 1080p monitors in 5 and 7 inch sizes and have a host of useful tools like vector scopes and waveform monitors.