why do eyes appear red in photography?

Answer 1

This only occurs when using a flash, because the intense light beem hits the back of the eye and reflects back the red color. To reduce this, the flash should be as far away from the shutter as posible, that's why you see wedding photographers with those huge brackets, it moves the flash further from the lens. Red Eye Reduction modes in cameras work by emitting several bursts of light before the shutter opens in order to shrink the iris in your eye, and make the red reflection smaller or not so apparent.

Answer 2

The flash gets reflected off the retina inside the eye. A redeye mode on your flash causes it to prefire several times before you take the shot in order to cause people's pupils to contract, so you can't see this.

Note that the light coming off the inside of your eyeball isn't actually red. We don't see people's eye glow red in bright light, for instance. It is a mistake in the lens system that bends that light into the red. You see a similar phenomenon called purple fringing in which there appears to be a purple outline around high contrast areas in a photo (ie the dividing point between very bright and very dark areas, looks purple).

A high quality lens reduces or eliminates these phenomena. You should not see redeye on an expensive camera (over $800).

Answer 3

You won't see it on an expensive camera because the flash is further away from the lens than it is on a cheap, small camera. It has nothing to do with the quality of the lens. If the flash is close to the lens, you will get a red reflection coming back into the lens from the subject's retina, but if the flash is a few inches above the lens, the glare from the retina does not enter the lens. It's simple geometry.

Answer 4

I'll make a guess..because the flash of the camera is reflected in their pupils sort of like when you see a deer on the side of the road when it's dark of course you see yellow in theirs. Hope that helps.