Everybody has seen the bright red eyes that sometime show up in flash pictures. Red-eye first reared its ugly head with the Kodak Pocket Instamatic of 1973. Poor design put the flash directly over the lens where the flash could reflect directly off the subject’s retina and back to the film.
Red-eye is now more common than ever as camera manufactures keep putting the flash head too close to the lens. Often the size of the camera gives them little choice. The problem can be solved in several ways.
1. Don’t use on-camera flash. Use natural light or off-camera flash.
2. Make sure there is enough room light that the subject’s pupils are not wide open.
3. Pre-fire the flash so that the subject’s pupils close before the actually picture is taken (this is a very-odd but common solution provided by many camera manufactures.)
4. Retouch out the red later. (This is far easier with digital than with film.)
Professional photographers seldom have problem with red-eye because we seldom use on-camera flash except as a fill. And red-eye was not an issue before 1973 because until then it was not possible to get the flash so close to the lens axis that it would cause a problem.
So that’s the story on red-eye. I hope this will help you tame this ugly dragon.