"Mark" wrote in message
"Craig Flory" wrote in message
Has anyone ever explained why red eye happens ? When the flash is too close to the lens light goes through the outside of the eye and lights up the small blood vessels and that is why it looks red. Professionals, like myself, don’t get it because we have the flash at least a foot or more above
the lens. I know this is not what you asked … but sometimes knowing why something happens can be a help.
Craig Flory
Is it really the small blood vessels or the passage of light thru the pupil and reflecting back that causes red eye????
Cats don’t have green blood vessels.
And it isn’t "really" necessary to have the flash a "foot or more" above the lens–2-3 inches for a good camera mounted flash that has the correct angle is sufficient to do the trick….
Mark
"The angle of reflection is equal to the angle of incidence." The reflecting surface in the eye is a very small target, accessed thru a very small ‘tunnel’.
The idea is to have the flash far enough removed from the lens so that the reflected light comes back an an angle that misses the lens. Is your flash far enough removed from the lens? Try a shot straight-on and see. Else: "Caveat raptor!"
Incidentally, I *hate* the red-eye preflash on cameras. "Alert, everybody! Here comes the picture! Everyone tense up!"
Good luck! . . . . patrick