In 2006 a pair of mathematicians, Nic Svenson and Piers Barnes of the Australian Commonwealth Scientific and Research Organization, determined the number of photos you needed to take of a group to ensure that one photo had everyone’s eyes open.They even won an Ig Nobel Prize in Mathematics for their work.
Severson and Barnes combined the average frequency and time of blinking with some basic statistics. It turns out the for groups less than 20, divide the number of people by three in normal light, or two in low light. So, the next time you are taking photos of a group, take a few extra photos and there is a good chance that one of them will have everyone’s eyes open.
For the more details on this calculation see Blink-free Photos Guaranteed.
About Mark Mizen
I have over twenty years professional experience in all aspects of photography and digital imaging. I am Chair of the ISO WG5 TG2 committee responsible for physical properties and durability of imaging material and am currently with HID Global working on systems for security printing for IDs, licenses, and credit cards. Previously, I was Director of Digital Development at Creative Memories from 2009 to 2012 and was responsible for the Creative Memories digital products and services. I also established and directed the Creative Memories Technology Center, which evaluated new products prior to product introduction, assisted with production difficulties, and provided technical information to support product sales.