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What is the focal length of the human eye?

What is the focal length of the human eye? Hhhmmm… I don’t really know. But here are some of my thoughts about this.

1. 50mm? –> the so-called “normal or natural” focal length is 50mm (on a 35mm format) because it is the nearest to what the eye can see both on the angle of view and perspective. How to arrive at 50mm? It’s basically the diagonal length of your sensor or film which is roughly around 43mm (I didn’t bother to compute though). Hence the closest focal length is 50mm. Actually a 40mm or a 45mm lens is closer. No wonder the shots from the 50mm are the closest to what we see in reality, in terms of depth, the angle of view and perspective. That’s why we call it normal or natural?

2. 24mm? –> for one eye is 50mm, but we don’t see the world with one eye right? So, if both eyes, it must be around 24mm? But both eyes overlap each other… and yeah, we are talking about “one” eye. I think our eyes can see as wide as 24mm. It’s only that the focused area is roughly at 50mm, but the periphery is wider, around 24mm. An example is you read the book and focus on it at the center (50mm), but you can’t read and interpret the ones at the sides without moving your eyes (24mm).

3. 14mm? –> some say it’s close to the rectilinear widest angle. It doesn’t matter if it’s in focus or not, the angle of view is what counts. I think you can see as wide and your mind can interpret it too without moving your eyeballs a bit. Though the interpretation at the extreme sides will be limited and not as detailed as compared to the ones within the focus of our eye in the center.

(While I was writing this article, I had my share of trying to squint, blink, focus my eyes and figuring out what the heck am I doing LOL! Hope you tried it yourself… haha!)

What is the best lens in the world?

Now you know the answer I don’t need to tell.


Focal Length Human Eye

Little Girl Eyes

Photographer’s note: F/1.4, 1/8000, ISO 200, Nikon D3, Nikkor AFS 24mm 1.4

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  • Hazel Alvero - To see is to believe. Need to get myself a full frame! hahaha! thanks for sharing! 🙂ReplyCancel

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