Red-eye that appears in most flash photos is a common problem today. At the back of the eye, retina reflects flash light emanating from camera. This type of reflection is one of the major causes of red-eye in flash pictures.
Additionally, red-eye in photos may appear due to larger surface area provided by iris when in low-light environment (Sollars et al. 603). It is worth pointing out that individuals who take photographs normally use flash when in low-light conditions and as such the surface area provided by iris may cause red-eye effect.
The emergence of digital photo technology is yet another reason why red-eye appears in flash photos (Sollars et al. 603). It can be attributed to a small or lack of space for films and internal mechanics compared to other cameras that use films. It is also important to note that a digital camera has its lens closer to the flash.
Consequently, when a picture is taken using a flash, the red-eye occurs since reflection from the iris part of the eye takes place when flash enters it. Thereafter, the reflected light goes back to the camera.
Today, most digital shoot and new point cameras being used have been modified in such a way that lens is situated right below and close to the flash. This enhances red-eye.
Furthermore, lack of tapeum lucidum is another known cause of red-eye in photos. Color pigment found in epithelium of retina gives out the fundus color which in effect causes red eye. Reflection of the flashlight by the fundus is recorded in the camera.
Most cameras lack an option for eliminating red eye (Rosolen et al. 145). Similar to digital cameras, they do not have room for adding an external flash away from the camera for lack of a hot shoe.
The reduction feature found in most cameras today cannot fully eliminate the red-eye problem even with a pre flash prior to image exposure by the camera. The reduction feature only causes the actual picture to have a small iris.
Discuss why animal eyes glow green when illuminated at night.
Animal eyes have cone and rods. These are important light receptors that help them in dim light conditions to function well. At night, nocturnal animals which are usually known have less cones and more rods are able to visualize motions and gather light for easy navigation from distant sources such as stars and moon (Sollars et al. 603).
The reason why green color is seen when light illuminates their eyes is due to the membrane at the back of their eyes which resembles a mirror. The spooky eye shine is a glow in the eye when bright light is shone through their eyes.
Besides,the strength of light reflected tends to be higher than its normal strength when originating from retina due to the tapetum lucidum (Rosolen et al. 145). This reflection from the tapestry of cells enhances vision of animals and appears green under spotlight. Different animals exhibit varying colors when tapetum is reflected.
Additionally, it is important to note that not all light that enters eyes are absorbed into retina. However, an animal uses what has been absorbed and reflected back from tapestry of cells to manage vision. At night, animals gather light from distant illuminating objects sources such as stars and moon.
The very light is reflected in the retina to enable night vision. The ricocheting of that light during illumination of animals’ eyes at night is seen as green color (Rosolen et al. 145).
Works Cited
Rosolen, Serge G. et al. “The ERG of the beagle dog: evidence associating a post b- wave negativity with the tapetum lucidum.” Documenta Ophthalmologica 110.2- 3 (2005): 145.
Sollars, Patricia et al. “Melanopsin and non-melanopsin expressing retinal ganglion cells innervate the hypothalamic suprachiasmatic nucleus.” Visual Neuroscience 20.6 (2003): 601-610.