Discuss why animal eyes glow green when illuminated at night. What causes “red-eye” in flash pictures?The unique eye shine emitted by many animals, comes from a mirror-like layer of cells behind the retina known as the tapetum lucidum. Some of the light entering the eye is captured by the retina, while some of the light penetrates through it. The tapetum lucidum reflects the light back to the retina, hence giving the animal a second chance to see it. It is this rebounding light that gives off the elusively eerie glow is associated with “red-eye effect in photographs or flash pictures.
This essay discusses how animal eyes glow at night when illuminated, the red-eye effect and chromatic abbreviation in a lens (Richard, 14).Not all light is absorbed by visual pigments in the retina. Some of it penetrates through the visual pigments. When this bouncing occurs with the light that comes into the eyes, the animals effectively intensifies the quantity of light accessible for the eyes to see with. Therefore, increasing the capability to see in the darkness. With human beings, the eyes mirror light, however, does act like a reflector.
Human eyes appear red in some flash photographs as a result of the camera flash bouncing off the red blood vessels and red tissue in the retina. This happens when using a photographic flash up close a camera lens, in relatively low light (Richard, 14).The red-eye effect appears in the animal and human eyes that do not have tapetum lucidum. The red-eye effect is as a result of the color of the fundus, a pigment predominantly positioned in the retinal pigment epithelium. The fundus color is a result of melanin pigment.
When the light coming from a flash happens too quickly for the pupil to close, plenty of the very bright light from the flash penetrates the eye through the pupil. Due to this, the fundus at the retina is reflected off and out through the pupil. The camera registers the reflected light and emits it as a red-eye effect (Richard, 14).Discuss chromatic aberration in a lensChromatic Aberration is a typical optical problem that happens when a lens is incapable of conveying all wavelengths of color to the same focal plane.
Chromatic aberration can also occur when the wavelengths of colors are concentrated on different locations in the focal plane. Chromatic aberration is initiated by lens scattering with different colors of light drifting at varying speeds while passing through a lens. This causes the image to appear blurred or perceptible colored edges seem around objects, especially in high-contrast conditions (Nave, 2015).An ideal lens would concentrate all wavelengths into a particular focal point, where the ideal focus with the circle of minimal misperception is situated.
A lens will not focus varying colors in precisely the same position because the focal length relies on bending of light and the index of refraction for short wavelengths such as blue light, is larger than that of long wavelengths such as red light (Nave, 2015).The quantity of chromatic aberration relies on the distribution of the lens. The use of glasses of varying dispersion in a doublet or other combination is one way to reduce the chromatic aberration. Chromatic aberration exhibits itself as bands of color along edges that discrete dark and bright parts of the image.
This is because each color in the optical spectrum cannot be concentrated at a single common point. Subsequently, the focal length of a lens is reliant on the index of refraction. Therefore, different wavelengths of light concentrate on variant places (Nave, 2015).Works CitedNave. “Chromatic Aberration”. Hyperphysics.. N.p., 2015. Web. 17 Feb. 2015. Richard, Vanita. Tools and Techniques in Digital Photography. New Delhi: World Technologies, 2012. Print.