Checking the sensor size?

[Ssayer]

Ok, so the last IP cams I got are sold by a number of vendors with a 2.8mm lens and a 1/2.5 sensor which state that they are good to light as low as 0.005 lux. I found a similar cam but with specs that say it's a 2.8mm lens and a 1/2 sensor and good to light as low as 0.0005 lux. I have my doubts but if it's legit, I'm in for it... so question is... how do I check, without disassembling the camera, the size of the sensor? It's Amazon, so if I opt to try it and it isn't, I can return it just like I've returned dozens of other cams for false or misleading advertising, so... (yeah, I have zero problem returning stuff if it isn't what it says it is)

 

[alastairstevenson]

There are at least a couple of other aspects beside sensor size that affect low-light sensitivity - the lens aperture size and the sensor model and manufacturer.
Product specs don't always help buyers make informed choices by including them.
Check if the camera specs you're looking at include these :

A larger aperture puts more light on the sensor and increases sensitivity, though at the expense of reduced depth of focus.
It's usually stated as the F-number, such as F1.2
But there is no guarantee that the aperture quoted with the sensitivity is what's used in the camera. (check out the Hikvision specs ...)

And there are many sensor manufacturers, with different performance capabilities and different price points.
Sony made a big leap forward with their back-illuminated designs (Starvis), other manufacturers had to catch up, or sell less-capable sensors at cheaper prices.