Hugh Brownstone on A7S3 Overheating...

Started Aug 3, 2020 | Discussions thread
underxposed59 Contributing Member • Posts: 834
Re: Hugh Brownstone on A7S3 Overheating...

Pete_vB wrote:

As I commented to Hugh on his his video, I came to a similar conclusion re overheating being due to direct sun exposure after looking at various videos. I'm an engineer specializing in thermal with experience ranging from automotive to consumer electronics and more recently solar thermal power. I suspect that in this direct sunlight condition Sony's cooling design is actually working against it.

To understand why one must first realize that a piece of black plastic or metal left in the sun on a hot, relatively windless day will get HOT- approaching 200 degrees F in the right conditions. If it was painted white it'd reflect most of the sun's energy and stay far cooler, one reason big telephoto lenses tend to be white- staying cooler means they suffer less thermal expansion making them more optically stable. The camera body on the other hand is black...

The noon sun has around 1000 watts per square meter of power, so if you whip out a calculator and ruler to measure the shadow cast by the camera you'd likely find the camera body is absorbing nearly 10 watts of energy from that sunlight. 10 watts doesn't sound like a lot until you realize that the FZ100 battery is only 16.4 watt hours, meaning if your battery lasts for 2.5 hours while recording the entire camera's only using about 6.6 watts of power (essentially all of which turns into heat). So by placing the camera in the noon sun you're over doubling how much energy the camera needs to get rid of, at which point the issue starts to become clear.

Panasonic's solution to this issue with the S1H was to move air THROUGH the body, effectively increasing the total amount of air the camera is exposed to. Sony on the other hand chose to avoid this, likely (from the press release, I have not seen images of the chassis) turning the entire body itself into one big heat-sink to efficiently get the heat from the processors, etc to the surface of the camera where air can take it away. And normally that should work fine... but if you set the camera in the hot sun with the top surface trying to get to 180F+ degrees it backfires: now your heat-sink/ chassis is providing a more direct path for the sun's energy to come IN. Other designs (like Cannon) which don't as effectively get the heat OUT may in fact last longer in these conditions because it takes the energy coming in the top longer to get to the electronics.

Thus I suspect this overheating in hot climates in direct sun may well prove repeatable, but this theory also suggests two potential solutions: A) A sunbrella as already mentioned. B) Put a bright adhesive white "skin" (or even white paint if you're feeling sporty) on parts of the camera that get sun. That should reflect ~90% of the sun's energy away, and if it's thin it shouldn't hurt conductive cooling...

That's my take anyway, we'll know soon as more tests are conducted.

Sony should have followed Minolta and offered the A7SIII in a special wedding kit

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