Peter C.
Veteran
I agree. People like to complain. There were 2 reasons for the lower resolution sensor. First: bigger pixels perform better in low light. Second: (more importantly) in order to do 120, 60, 4k, raw, 10bit, it takes a lot of processing power and generate HEAT. Each mirrorless camera has chosen how they will handle heat:Yes. It's interesting the 12-megapixel Nikon D3S was released in October 2009, and professionals managed perfectly well with it. Even the D4 (released on Jan 2012) had "only" 16.2 megapixels.
The D3S was $5300 USD in 2009, which is about $6280 today.
If you're a non-professional hybrid shooter, I don't see a hard-core video-centric camera like the S1H or A7SIII as being the best choice. If those are the people with 60-megapixel envy, those cameras aren't designed for them. If you're a non-professional enthusiast *video* shooter, those cameras are great. If you're a professional hybrid or photo-oriented shooter, you'll own more than one camera, which means one can be a high-megapixel photo-oriented model.
IMO it's as if Sony released a new 60 megapixel photo-oriented camera and as a videographer I complained it had rolling shutter on video, and could not do full-frame non-pixel-binned 4k/120 at ISO 409,000. There are tradeoffs to fully optimize the design for a certain use.
There's a valid point whether the A7SIII video design goals could have been met with a higher-megapixel sensor. If so no ILC manufacturer has done it, so with current technology the answer seems to be no. There would be issues with sensor scan time, CPU, thermals and power consumption. You could argue the S1H does OK but only needs phase-detect AF to be perfect, so why couldn't Sony have made an S1H clone with PDAF. Maybe rolling shutter isn't that big a deal, and the solution to heat is a fan. I guess Sony could have done that, and I'd have liked having Super35 crop mode.
But as a videographer I feared the A7SIII would either be crippled or not sufficiently video centric. I was hoping it would be more like the S1H, and it is (while not a clone). Another example: up to the last day before release, the rumors said micro-HDMI, but it ended up with a full-size HDMI port. It will even have ProRes RAW capability to Atomos, just like the S1H. It is very close to the best possible ILC video-centric camera at that price point, given current technology.
Sony: lower pixel count sensor
Panasonic: Larger camera, line skipping, cropping, or was it pixel binning?
Canon: Limit the time, let it over heat. Win win for them, it gives you a just a taste, if you want a video camera buy their cine line.

