Between Eye and Camera

Introduction

I want too clear you guys that what in between a human eye and a camera?

I am often asked by people and photographers what should be done to a photograph to make it match what we saw.
This is an important question because it addresses the differences between what we see and what the camera captures. It addresses the difference between our eyes and the camera’s image means the lens, filters, camera, film or sensor.
The differences between the two are not only notable, they are also damaging to the reality we see because the camera introduces numerous changes to this reality.

In order to create an image that matches what we saw, we not only have to become aware of what this damage is, we also need to learn how we can fix this damage. Only then will we be able to create an image that not only “matches what we saw” but also expresses how we felt when we took the photograph. Only then we will be able to create an image that represents what our eyes and brain saw and not just what the camera captured, an image which is not only a factual record of what was in front of the camera, but also a visual expression of our emotional response to the scene we photographed.

Similarities

First of all, both of them have an opening at the centre for light to enter aperture for the camera and a pupil for the eye. The camera has a diaphragm to control the size of the aperture (to control the amount of light entering camera/eye) while the eye has iris muscles to control the size of the pupil. Cornea is the main part of the eye (included are lens, aqeuos and the vitreous humor) that functions to refract light as a glass biconvex does in the camera. Photosensitive chemicals on the film of camera and photoreceptors in the cornea of the eye are the objects of light action to form an image and they both absorb excessive light to prevent multiple images formation using a dark internal surface in the camera and a pigmented, dark choroid in the eye.




And both the human eye and a camera use something called a lens. In fact, they both use the same type of lens - a converging lens. Converging lenses are like the ones in magnifying glasses - they work to make an image look bigger. This is why you can see the details in something even if it's on the other side of the room. One thing about lenses is that they can only focus on things that are the same distance away from them. This is why your eyes can focus on things that are close to you or far from you; just not at the same time. Cameras are the same way - you can only focus them on things that are the same distance away.


In the camera, the lens focuses the light onto a piece of film. The film has chemicals in it that basically trap the image on it, making it permanent. Instead of film, your eye uses something called a 'retina.' The retina has lots of little tiny things called 'rods' and 'cones' all over it. These are basically tiny antennae that tell your brain about the light that hits them. The rods tell your brain if there's light in a certain spot or not (a bit like a black and white photo) and the cones tell your brain what color the light is.

There is one spot on the retina, though, that has no antennae at all. This is the spot where the nerve leaves your eye to go to your brain. At this spot, you can't see anything at all - it's called your 'blind spot.' This is one of the reasons that you have two eyes; what you can't see with one eye you can see with the other. Unlike your eyes, cameras have no blind spot, so they only need to have one lens.

Another important thing about seeing light is that you have to be able to control how much light gets in... otherwise, you couldn't see things in a brightly-lit room because you'd be overwhelmed by how much light there is. Your eye controls how much light gets in by changing the size of the pupil - the dark spot in the center of your eye. The more light there is, the smaller your pupil becomes, and the less light gets in. Many (but not all) cameras also can adjust to let different amounts of light in. This way, your outdoor pictures don't look washed out and your indoor pictures don't look too dark.


An interesting thing that I learned about pupils is that your pupil will also change size depending on what sort of mood you're in. But you sure can't tell the mood of a camera just by looking at it!





Differences

The fact is that the eyes uses living cells while the camera is artificial just like the eye focus the image using the retina while the camera changes the position of the lenses and the amount of light enters the eye is control by the iris while in camera it is by the diaphragm.

Cameras can take pictures, your eye can only process it to your brain so that it goes to your memory. Cameras don't lose their memory unless you delete it, unlike your brain which often tends to.

The contemporary camera is an electromechanical device, and the eye is a biological mechanism. Both have a lens to respond to and focus electromagnetic energy (light), but the eye puts the light on and the main fact is that the eye can see better than a camera's lens
THE HUMAN EYE IS A SUBJECTIVE DEVICE. THIS MEANS THAT EYES WORK IN HARMONY WITH BRAIN TO CREATE THE IMAGES WE PERCEIVE: OUR 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 OUR BRAIN. IT IS CONTINUOUSLY READJUSTING ITS COLOUR BALANCE ACCORDING TO THE LIGHTING CONTEXT. IN OTHER WORDS, OUR EYES KNOW WHAT MUST BE SEEN AS RED OR WHITE OR BLACK ETC.

A CAMERA, ON THE OTHER HAND, IS AN ABSOLUTE MEASUREMENT DEVICE . IT IS MEASURING THE LIGHT THAT HITS A SERIES OF SENSOR, BUT THE SENSOR IS 'DUMB', AND THE SIGNALS RECORDED NEED TO BE ADJUSTED TO SUIT THE COLOR TEMPERATURE OF THE LIGHT ILLUMINATING THE SCENE, FOR EXAMPLE


Lens focus:
In camera, the lens moves closer/further from the film to focus. In our eyes, the lens changes shape to focus: The muscles in your eyes change the actual shape of the lens inside our eyes.
Sensitivity to light:
A film in a camera is uniformly sensitive to light. The human retina is not. Therefore, with respect to quality of image and capturing power, our eyes have a greater sensitivity in dark locations than a typical camera.

Mega pixels of our eyes

The retina contains about 100 million rods and cones.  If you consider each of them as a pixel then the human eye has more than a Cannon.
It's a bit more complicated than that, since the rods and cones are not evenly distributed on the retina and each has a separate color response.  
See:  http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html 
for some more information.