Saturday, 3 December 2016

light - Why do dog's eyes glow green on a photo?


Taking my current profile picture as a prominent example:


Dog's eyes glowing green in camera



This photo has been taken with flash. As I gather, this is the same effect that makes a human's eyes glow red on photos, namely the reflection of the flash at the choroid and then passing back through the retina.


The retina is full of bloodvessels and the blood inside them gives the reflected light it's reddish color.


If it's the same effect, why is the color different?



Answer



Dogs, cats, and many other mammals have a Tapetum lucidum which reflects light back through the retina to help with night vision. Humans don't have this layer. The tapetum is probably reflecting green light that would have normally been absorbed.


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