Not long ago I was working on this short, a very interesting project in which the director wanted to have an insert of a contracting eye. She wasn’t sure if shoot it on camera or if create it, during post production, with a special effect software of through animation.
I was determined to make it in camera. We discussed it for a while and in the end we decide to try to film the pupil dilating and then reverse it in editing. Now how you going to be able to capture on camera a dilating eye? The first question to be answer was when is it the the eyes dilated? It is when you go for a darker place to a bright one. Ok, so we know that we need to have the actress stay in the dark for a while and the get her to the light. But for how long she need to be in the dark? And she can not simply walk from one room to an other because the pupil dilates in seconds. Plus we need to shoot almost completely open this means a very shallow deep of field. We try a couple of different way during the day and non of them work. So we decide to shoot it in the end of the evening after the sunset.
We set up a 650 almost straight in front of the actress a little higher the her, but aiming at her face. The actress has her back against a wall so that she wasn’t change her distance from the camera, so we were sure that her eye was on focus. After the camera was set up and the actress was in position we switch off all the light in the room and we stay in the dark for 5-6 minute, may be something more, after rolling the camera we strike the light. And magic happen!
We go it at the first take but for safety we did a second take. We decide to shoot it in slow motion Because the reaction time of the human eye is very fast and we want to be sure we have enough seconds to be able for the audience to see properly.
My suggestion is if you can shoot it in slow motion to stay on a save side, and to avoid that you actor/actress close the eyes tell he/her when you are striking the light so that he/she can be prepare.
I have to admit that was a real satisfaction be able to film me it on camera and not having to do it in post.