No, your brother-in-law is not a vampire !
How many weird pictures do we find in our photo albums that show the same red eyes genetic trait in friends and family members? All of us have produced this phenomenon, whatever camera we use.
What's Going On?
There is a very simple explanation. First of all, you must understand that this only occurs when pictures are taken with an electronic flash. When the subject is located in a dark, poorly lit room, the pupil of the eye is dilated. If you take a picture at this time with a camera equipped with an integrated flash located very near the objective, as is the case for most cameras, the flash hits the back of the eye, which is profusely supplied with blood vessels, thereby creating the red eyes effect.
How Can This Problem Be Solved?
With a basic camera that cannot be adjusted
If possible, increase the lighting level of the room so that your subject's pupils close a little, or use more sensitive film (e.g., ISO 800) so that you may take your pictures using only the available lighting without a flash.
Cameras equipped with a "red eyes" feature have been available for several years
This feature activates a first quick flash just before the main flash. This forces the pupil of the subject to contract in response to the light before the picture is taken.
Third solution for reflex cameras with a flash shoe
Adding a backup flash to your camera will pull the flash away from the axis of the objective. This will have the added general advantage of providing more powerful lighting, something quite significant when extensive spaces are involved.
Your images are already printed
It is possible to touch up the printed picture with an inexpensive felt pen to eliminate red eyes. However, results vary depending on the picture and paper surface.
Your images are digital
It is possible today to employ user-friendly software to quickly touch up red eyes with a specially designed tool.
Your lab or photo shop can also make these corrections when they are printing your pictures with their own equipment.
To conclude, your brother-in-law is certainly not a vampire, but watch out anyway, he might still be an extraterrestrial, a clone, or God only knows what.
Go for it, and Happy Shooting!
With the cooperation of Jacques Bourdages, PFE