Sometimes when someone takes a photo, it is noticed that people's eyes show a red spot. It's not happen all the time, What are the reasons when happens? and why other mammals' eyes (like cats, cows, horses...) do not show that characteristic? In fact, they show bright eyes in photos.
2006-06-05 23:21:17 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Biology
And why is not observed in other mammals like cats, dogs...?
2006-06-05 23:35:44 · update #1
It's light bouncing off the back of the inside of the eye. The camera catches it before the iris has time to contract in response to the higher light level. I've seen the red eye effect firsthand, in real time. A cousins baby was staring up at a streetlamp, quite creepy. Animals have a reflective membrane, the 'tapetum lupidia' behind their photoreceptor cells that bounces light back through them, the photo receptors that is, it gives them better night vision by giving the light two chances to hit. We don't have one because our color vision comes with the cost of poor sensitivity in low light.
2006-06-06 09:29:39 · answer #1 · answered by corvis_9 5 · 4⤊ 0⤋
I concur. The red is the refection of blood vessels in the eye.
Humans lack the reflective properties in the eyes that cats and dogs have.
Some digital cameras have 'red-eye reduction' where the flash will pulse several times before taking the photo. The idea is, the pulses will cause the iris to close a little, minimising the red -eye effect.
2006-06-05 23:50:21 · answer #2 · answered by Xraydelta1 3 · 1⤊ 0⤋
These are all great answers: I just thought I'd add my 2 cents worth. If someone has cataracts, the red eye won't be there (or will be lessened). Cataracts are opacities in the lens which blocks the light reflex (light bouncing from the retina).
2006-06-06 10:06:22 · answer #3 · answered by J 4 · 0⤊ 0⤋
it is the reflection of the flash inside the eyeball. We know that at night the black part of the eye becomes wider, so it may allow the eye to get more light in darkened areas, so when this is wider the flash light can enter inside the eye, and reflects the blood.
2006-06-05 23:29:32 · answer #4 · answered by Djaber N 1 · 1⤊ 0⤋
Redeye effect. It's cos of the blood in the vessels in the eyes making it's presence felt.
2006-06-05 23:26:04 · answer #5 · answered by Dilliwala 2 · 0⤊ 0⤋
the flash when shone directly into eyes reflect the blood vessels in the eye.
2006-06-05 23:26:20 · answer #6 · answered by beltman 3 · 1⤊ 0⤋
its ur camera fault cover it,
2006-06-14 03:11:40 · answer #7 · answered by Khusi 2 · 0⤊ 1⤋
May be your's, not mine
2006-06-05 23:24:39 · answer #8 · answered by paathu 3 · 0⤊ 2⤋