I – Comparing the Human Eye and a Camera

An inquisitive mind excels in a continuous, life long learning process. A common way to start learning about something new is getting to a vantage point first and having an overview of the landscape ahead. Only then starts the laborious dive into the experts intricacies. Tenacity allows unaccountable small steps to end with a comprehensive understanding of the complexities. Finally, the novice becomes a master when the matter is not just understood in all details, but contributions with answers and expanding solutions can be given.

A novice to the art and science of photography gets overwhelmed at first. A camera has a multitude of functionalities which require an understanding. Aperture, shutter speed, light sensitivity, focal length, and depth of field are mind cluttering concepts for the novice. A brilliant simplification in such a moment is to engage the apprentice with the idea that the camera works just like a human eye.

I remember what my reaction, barely a teenager, was at that moment.

Mentor: Peter, this is easy, your camera works just like your eyes.
Me: Oh! (I’m sure that my puzzled look in my face did not escape my mentors attention)
Mentor: You see, the iris has an opening (your pupil) which adjusts to the light intensity of the environment. A lot of light makes your pupils go smaller and dim light opens them up. Your eye lens gets thinner and thicker according to the distance between you and your object. Finally, the film (nowadays the sensor) is your retina.
Me: Ah! (big pause to digest the earth shattering insight) OK, seems simple, I got this!

As a teenager I really didn’t know a lot about eye physiology, but the oversimplification worked well. I got out there and started to create my images. The years passed by, I’m not a teenager and a novice anymore. Photography is a “serious” hobby of mine and medicine is my profession. The comparison between a camera and an eye helped me to overcome my first inhibition towards the complexity of a SLR camera, but when I mentally go back to that eureka moment now, I have a smile on my face.

The eye and the camera do indeed have a common denominator. They record light sources and reflected light. Nothing more, nothing less! Any similarity ends here as the eyes are just a little part of what allows living beings to see its surroundings and a camera is only one of the many tools required to provide us with the final product – an image on a screen or on a wall.

II – Part of a Whole

The fact that the eye and the camera are just little parts of the holistic process between seeing the environment and having an image on a screen or on the wall, respectively, sounds obvious. Some might even think that it is ridiculous to point out such truth. However, by looking at these details and dissecting the differences, also allows us to really appreciate what we have with the Human Visual System (HSV) and with the Photographic System. The one is not better or worse then the other. There are only significant differences. One complements the other making both better together.

Human Visual System – The two eyes are just part of this highly effective and unique biologic light recording system. The indispensable physical elements of the eye involves the cornea, aqueous humor, iris, vitreous humor and finally the retina. The latter has two types of photoreceptors:

  • cones which cluster at the fovea: detect color at bright light, provides greatest visual acuity, and
  • rods spread at the back of the eye providing general vision.

The photons trigger a biochemical reaction to the cones and rods which is passed on through the optical nerve, partially crossing at the optic chiasm and ending up in the posterior brain (occipital) lobe where it is processed to the final instantaneous image. Let’s not forget that at the same time all other 4 senses are equally being processed and at the end we have an all encompassing experience which is not isolated to an image.
Imagine following moment, we are at the beach. We see the scenery unfold to our eyes, we smell and might even taste the salty air, we hear waves crashing on the sand and the seagulls squawk, we feel the cold water on our feet and the breeze on our skin and hair. We walk along the beach without any problems as our eyes are constantly adapting to the light conditions and we don’t bump into any rocks or sea urchins as our dual vision system gives us a clear feeling of space. Life is good and we might carry this moment in our memories for the rest of our life.

Photographic System – We are emerged in the moment of being on the beach as described above. We carry our heavy photographic gear with us and craft some images. The light penetrates the lens of our camera. It is measured and gives us a reading of its intensity. Aperture, shutter speed, ISO, white balance will be adjusted accordingly. The lens will be adjusted to get the right sharpness or we might even need to change our lens to a different focal length to achieve the right framing. The camera trigger is pushed and a first image appears on the back of the camera. We seem to be satisfied with what we see on the screen and head home to feed the image to the computer. A smile appears on our face once we see the image to present itself on the screen with help of the post-processing software. Some digital tweaks are done to the image and finally we post the image on social media or print it and hang it on one of our home wall. Both presentations are obviously two dimensional. Whenever we see the image again we have these same fuzzy feelings we had at the time we were on the beach and crafting the image. Other people see the same image and don’t see anything else, but a nice beach scene and move too quickly on to other life topics. Very few will stop in their tracks and be in marvel about the beautiful recorded scene despite the absence of tasting and smelling the salty air, not hearing the crashing waves and not feeling the breeze on their skin and hair.

This a very succinct essay in exploring the differences between our two visual systems – the human visual system and the photographic system. Yes, there is a similarity between the eye and the camera, just as there is a similarity between an apple and an orange. Both are edible fruits and that is it!

Following essays are to be published every two to three months and illustrate topics regarding the human visual system and the photographic system. The topics will vary from technical aspects (composition, exposure, histogram, etc.) to philosophical/cultural moments (experiences, thoughts, emotions out there in the Southwestern wilderness and trips abroad).