1/(Focal Length) = 1/(d1) + 1/(d2)
That is the math shown by the light in the photograph. This is a wonderful shot by Zack DeZon of Zack DeZon photography. I really like the illustrated fact of the focal math. I wrote him to send my compliments and he graciously gave me permission to post his shot with a link to his site. Link? You bet! Plus my person endorsement of his work. I looked around his site. I'm no aspiring actor, but if I were he would do my head shot for sure.
