(I’ve got a Sony A7s and sometime use a friend’s A7rii, so I’m interested in sharing this article to our Sony camera viewers…)
Technically, there are two sides of the problem to solve: internal and external camera overheating. In other words, even if you are shooting indoors with a comfortable temperature level, the heat from the internal parts of your camera will eventually shut it down. On average, it may take 20 to 40 minutes of HD video recording before you see the overheat warning. Yet, direct sun rays worsen this situation, and if you’ve ever tried shooting 4K outdoors on a sunny day, you probably know — several minutes are the maximum you can get.
Before jumping into non-obvious ways to prevent overheating, remember that the first rule of working in the sun is keeping your gear in a bag or at least covered with a light color piece of cloth all the time while not shooting.