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Ask Science – How Many Megapixels Does the Human Eye Have?

Ask Science – How Many Megapixels Does the Human Eye Have?

Jun 26, 2012

Can you measure the human eye with megapixels, and if so how many megapixels is the human eye?

Yes and no. There are about 120 million rods (black and white receptors) and about 5 million cones (colour receptors), so the total resolution of your eye would be about 125 megapixels… But you can’t really stop the comparison there, since about 5% of your retina at the center of your field of vision contains about 50% of your photoreceptors (this area is called the fovea). The resolution of your eye drops off drastically the further away from the center you go. So, realistically your eye is about 50 megapixels in it’s densest regions before it goes almost blind at the edges of your field of vision…

But it doesn’t end there… There is so much image processing done in your eye, and in the thalamus region of your brain (the bump right above your neck at the back of your head), that it’s hard to tell what you’re actually seeing and what you merely perceive to be there. That’s why optical illusions work so well on us and why eye witness testimony is considered to be the some of the least reliable evidence in our judicial system. It’s way too easy to visually hack our brains, and see things incorrectly or things that don’t exist at all.

So, there is no direct comparison between the layout of phototransistors on a CCD, and the layout of photo receptors your eye’s retina. The amount of detail your brain fills in, muddies the comparison even further, almost to the point where you can’t really say you’re talking about the same thing at all, when you compare digital vision and organic vision.