The Human Eye and TheCamera How they are similar and how they are different. Lily-Belle Cote
I chose this topic because being a photographymajor I have always been interested in how boththe Camera and the Human eye capture andrecord images. I really enjoyed completing thisproject, I learned that the Human eye and theCamera have a lot more in common than I wouldhave 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 PupilBoth anaperture of acamera and thepupil of the eyeboth functionas an openingfor light toenter.
The way the aperture and pupil work to controlthe amount of light entering the camera/eye isslightly different though. With a camera thediaphragm controls the size of the aperture whilein the human eye the iris muscles control the sizeof the pupil. But both can allow a smaller openingthat let less light in bright situations or largeropenings that let more light in darker situations.The light then travels through the openingthrough the lens or eye.
Focusing the imageWhen it comes to the focusingmechanism, while itaccomplishes the same thing,the eye and the camera havedifferent methods of focusing.To change the focus on acamera one must change thedistance between the lens itselfand the film; while in thehuman eye the ciliary muscleschange the actual shape of thelens inside the eye.
Because of the muscles controlling themovement of the lens in the eye, the human eyeis a lot more flexible compared to the commoncamera. Camera lenses are rigid because theyare controlled by moving the lens to change thedistance between the lens and the film.
Forming an imageIn a similar sense, both the human eye and thecamera, retain information to form an image. Thelight travels through the aperture or the pupil,focuses through the lens, and then is recordedbut how the image is recorded is different. Thecamera retains this information by chemicals thatare found on the film while the human eye retainsthe information by photoreceptors, rods andcones, in the retina. The retina is the lightsensitive part that captures the image.
Once the image has beencreated, the method oftransferring it is also different.With a camera, the film then hasto be developed before you cansee the final outcome. With thehuman eye, once the image hasreached the retina, thephotoreceptor nerve cells reactand send and impulse to thebrain via the optic nerve. In thebrain, multiple nerve impulsesreceived from the photoreceptorcells in the retina are composedinto a final image.
Retaining ImagesUnless you have photographic memory [theability to remember information or visual imagesin great detail] , for the most part, an Imagesaved on a Camera will have more informationyou can pull from later on. While all the sameinformation gets seen by the Camera and theHuman eye, the Human eye will focus on acouple key items while a Camera will captureeverything in the scene and record it to beviewed later.
InterpretationA very important aspect of comparing the humaneye to a camera is how both interpret the visualinformation they capture. The human eye worksin harmony with the brain to create a perceivedimage. The brain is constantly adjusting the colorbalance according to the lighting, that causeshuman eyes to know automatically what is seenas red, black, blue etc. While a camera is anabsolute measurement device, it measures lightthat hits a series of sensors but those signalsmay need to be adjusted to create the image thatis actually happening.
TermsCiliary body – A structure located behind the iristhat produces a fluid that fills the front part of theeye, it maintains eye pressure and also allowsfocusing of the lens.Cornea – the outside layer of the cornea isknown as epithelium and its main use is toprotect the eye.Iris – Is the part of the eye which is responsiblefor eye color. It acts like the diaphragm of acamera, dilating and constricting the pupil toallow more or less light into the eye.Pupil – Is the dark opening in the center of theIris that controls the amount of light entering thepupil.
Lens – The part of the eye behind the Iris thatfocuses light rays onto the Retina.Optic Nerve – Is the structure that takes theinformation from the Retina as electrical signalsand takes it to the brain where the information isinterpreted as a visual image. It consists of anerve bundle containing approximately onemillion nerve fibers.Retina – Is the membrane lining on the back ofthe eye that contains photoreceptor cells. Thesephotoreceptor cells react to the presence of lightby sending an impulse to the brain through theoptic nerve.