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Old 03-26-2018, 08:17 AM   #9
whswhs
 
Join Date: Jun 2005
Location: Lawrence, KS
Default Re: Infra-red vision vs. dark vision...

Quote:
Originally Posted by Anthony View Post
Well, a bit better -- 20:20 vision requires a pupil size of around 4,000 wavelengths, which is 1.6-2.8mm for the visual spectrum, and probably around 35mm for a reasonable thermograph, so a pupil dilated to 7mm might approach 20:100.
But it's not only pupil size. It's also how closely spaced the receptors can be. Human retinal neurons are as close together as is permitted by the wavelength of visible light. If you go to thermal infrared wavelengths you need the neurons to be more widely spaced.
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