My family took a lot of pictures this week at Christmas. A lot. Every possible combination of cousins, aunts, uncles, and siblings had their time in front of the camera. When I was going through cropping, I spent a fair amount of time editing out red eye. It probably would have been easier to stop it from the source, but I have no idea how to go about doing that. Turns out its really just basic optometry!
Red Eye happens when the flash occurs too fast for the pupil to constrict and adjust to the light. The bright light passes into through the un-dilated pupil into the eye and reflects off of the fundus at the back of the eyeball. The light appears red on film because of the blood vessels in the back of the eye. So, instead of photographing the iris the camera captures the back of the eye.
Red-Eye functions on cameras produce short flashes of light prior to taking the photo, which gives time for the pupil to adjust and constrict to normal size. Not looking directly at the camera lens might be enough to shield your eye from the flash and avoid dilation, or you can increase lighting in the room to allow more constricted pupils.
Other factors can affect red eye. Consuming alcohol slows your bodily functions, which includes your pupils’ response time. It is common knowledge in the optical world that light eyes are more susceptible to light. Meaning people with light eyes will probably have red eye more frequently.
Good luck reducing your red eye!
