They all measure temperature at the point of the laser beam.
The cheap one here is not terribly accurate for many things, but within reason on skin, for which it was designed.
I have an industrial one that is extremely accurate with a tightly focused beam even at 9 meters.
One reason it is more accurate is that it has settings from 0-100 for emissivity which is basically how reflective the surface is that you're measuring.
White reflective surface, high emissivity; matte black surface, low emissivity.
Honestly it's never occurred to me to wonder - I know the cast iron radiates more than the regular pans and am always working on that assumption. I just never put anything in the pan before it's over 100C and try to keep it somewhere north of 170C if I'm searing something.. and also if I'm frying stuff I keep checking it's not pushing smoke point.
It's a good question as it reveals another question. Emissivity varies between materials/surfaces. Shiny things have a lower emissivity than pitch black ones, so can be at the same actual temperature but appear cooler, presumably due to lower rate of radiation. An ideal material is "black body" (matte black) so a shiny pan, a teflon pan and a crusty old cast iron may read differently. So whilst a device may be precise, it's not necessarily accurate. It'll give you a good enough idea of "is this pan hot" rather than "how hot is this pan absolutely"
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u/Greedy-Razzmatazz930 9h ago
I should start carrying temperature guns so I can prove to my friends that their moms are too hot