It might not be completely as simple as it looks but there are a lot of good reviews, side-by-sides etc on this forum to draw some good conclusions. Also check out threads by member
@wopi82 for more technical details around the sensors themselves. Read the
Cliff Notes, packed with good first-hand notes from the contributors on these forums.
Look for sensors as large as you can afford, don't focus as much on total MP, and look for Starvis/Starlight/Darkfighter cameras which are known to do well in the dark (if that's what you need). You will also want to read up on Focal Length and how the aperture the sensor is looking through controls how much actual light makes it to the sensor (also on this site).
Sensors used in Dahua cams
https://www.ptgrey.com/support/downloads/11165 Not all sensors are listed, but it gives a nice overview of sensor types and manufacturers. And it looks cool :D
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Just noticed on the CCTV sensor site the imx485lqj. Same pixle size as the imx327. A 4k with the same night power of the 2mp starvis, yes please. Products Image Sensor for Security & Surveillance | Sony Semiconductor Solutions Corporation
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Dahua has released 4mp CVI cameras with the starlight+ designation using 1/1.8" sensors. IP versions probably not far off. https://www.dahuasecurity.com/products/productDetail/28077
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