The Human Eye and The Camera

How they are similar and how they are different.

Lily-Belle Cote

I chose this topic because being a photography major I have always been interested in how both the Camera and the Human eye capture and record images. I really enjoyed completing this project, I learned that the Human eye and the Camera have a lot more in common than I would have assumed.

The camera and the Human eye

The human eye and the camera have many similarities. All of the components found in both have a vital role in not only providing a clear image but also how that image becomes recorded.

How light entersAperture vs Pupil

Both an aperture of a camera and the pupil of the eye both function as an opening for light to enter.

The way the aperture and pupil work to control the amount of light entering the camera/eye is slightly different though. With a camera the diaphragm controls the size of the aperture while in the human eye the iris muscles control the size of the pupil. But both can allow a smaller opening that let less light in bright situations or larger openings that let more light in darker situations. The light then travels through the opening through the lens or eye.

Focusing the image

When it comes to the focusing mechanism, while it accomplishes the same thing, the eye and the camera have different methods of focusing. To change the focus on a camera one must change the distance between the lens itself and the film; while in the human eye the ciliary muscles change the actual shape of the lens inside the eye.

Because of the muscles controlling the movement of the lens in the eye, the human eye is a lot more flexible compared to the common camera. Camera lenses are rigid because they are controlled by moving the lens to change the distance between the lens and the film.

Forming an image

In a similar sense, both the human eye and the camera, retain information to form an image. The light travels through the aperture or the pupil, focuses through the lens, and then is recorded but how the image is recorded is different. The camera retains this information by chemicals that are found on the film while the human eye retains the information by photoreceptors, rods and cones, in the retina. The retina is the light sensitive part that captures the image.

Once the image has been created, the method of transferring it is also different. With a camera, the film then has to be developed before you can see the final outcome. With the human eye, once the image has reached the retina, the photoreceptor nerve cells react and send and impulse to the brain via the optic nerve. In the brain, multiple nerve impulses received from the photoreceptor cells in the retina are composed into a final image.

Retaining Images

Unless you have photographic memory [the ability to remember information or visual images in great detail] , for the most part, an Image saved on a Camera will have more information you can pull from later on. While all the same information gets seen by the Camera and the Human eye, the Human eye will focus on a couple key items while a Camera will capture everything in the scene and record it to be viewed later.

Interpretation

A very important aspect of comparing the human eye to a camera is how both interpret the visual information they capture. The human eye works in harmony with the brain to create a perceived image. The brain is constantly adjusting the color balance according to the lighting, that causes human eyes to know automatically what is seen as red, black, blue etc. While a camera is an absolute measurement device, it measures light that hits a series of sensors but those signals may need to be adjusted to create the image that is actually happening.

TermsCiliary body – A structure located behind the iris that produces a fluid that fills the front part of the eye, it maintains eye pressure and also allows focusing of the lens.

Cornea – the outside layer of the cornea is known as epithelium and its main use is to protect the eye.

Iris – Is the part of the eye which is responsible for eye color. It acts like the diaphragm of a camera, dilating and constricting the pupil to allow more or less light into the eye.

Pupil – Is the dark opening in the center of the Iris that controls the amount of light entering the pupil.

Lens – The part of the eye behind the Iris that focuses light rays onto the Retina.

Optic Nerve – Is the structure that takes the information from the Retina as electrical signals and takes it to the brain where the information is interpreted as a visual image. It consists of a nerve bundle containing approximately one million nerve fibers.

Retina – Is the membrane lining on the back of the eye that contains photoreceptor cells. These photoreceptor cells react to the presence of light by sending an impulse to the brain through the optic nerve.

Work Citedhttp://library.thinkquest.org/28030/eyeevo.htm

http://www.ehow.com/about_6331650_camera-work-like-eye_.html

http://www.pasadenaeye.com/faq/faq15/faq15_text.html

http://www.pixiq.com/article/eyes-vs-cameras

http://www.cepolina.com/photo/technology/camera/2/camera_focus_spiral.jpg

http://fc02.deviantart.net/fs47/f/2009/231/7/e/35mm_film_III_by_indietextures.jpg