What’s the difference between a camera and a human eye?

Or: What’s the ISO of a human eye?

Haje Jan Kamps
Photography Secrets
9 min readNov 24, 2017

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I have worn glasses all my life, and as a result, I was introduced to the magic of optics way before I ever considered getting into photography.

Then, when I started learning more about the magic of photography, I started noticing things with my own eye-sight: For example, in bright daylight, I can see further than in twilight. Why? I’ll leave you to solve this one yourself (think about it!) — the solution is at the end of this article.

A quick anatomy refresher

As a photographer, I’m often intrigued by the physics of how photography is similar (and different) to how my eyes work — so I figured it was time to write a little article about how it all hangs together.

Camera vs Eyes: Similarities

To better understand the answer to this question, let’s first have a quick comparison of various similarities and differences found in the working of the human eye and a photo camera.

Image focusing: Human and camera lenses both focus an inverted image onto light-sensitive surface. In the case of a camera, it’s focused onto film or a sensor chip. In your eyes, the light-sensitive surface is the retina on the inside of your eyeball.

Light adjustment: Both the eye and a camera can adjust quantity of light entering. On a camera, it’s done with the aperture control built into your lens, whilst in your eye, it’s done by having a larger or smaller iris.

Camera vs Eyes: Differences

Absolute versus subjective measuring of light: Simply speaking, the human eye is a subjective device. This means that your eyes work in harmony with your brain to create the images you perceive: Your eyes are adjusting the focus (by bending the light through the lens in your eyeballs) and translating photons (light) into an electrical impulse your brain can process. From there onwards, it’s all about your brain: It is continuously readjusting its colour balance according to the lighting context. In other words, our eyes know what must…

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Haje Jan Kamps
Photography Secrets

Writer, startup pitch coach, enthusiastic dabbler in photography.