ALEXA shoots scene lit only by iPhone screens

ALEXA shoots scene lit only by iPhone screens

At a recent seminar in Los Angeles, cinematographer Bill Bennett, ASC, surprised his audience by revealing that the live feed image they had been looking at from an ALEXA camera was in fact lit by the luminescent screens of two iPhones. Bill's purpose was to illustrate the extraordinary low light performance of ALEXA; he describes the setup in more detail below.

I lit a rather unusual shot the other day at a seminar, to demonstrate the point that the ALEXA can make nice images in very low light levels. It was a scene lit with nothing more than the light from the screens of two iPhones. 

We hid the camera and lighting setup from the 40 seminar participants as they came in, putting it in a blacked-out office off to the side of the large meeting room. We were showing the "monitor out" image from the camera on the very nice Dolby PRM-4200 monitor, at the front of the room. Then after I spoke a little about how we were going to discuss the newest generation of digital cinema cameras - the ALEXA in particular - I had the audience members go into the office two or three at a time to see the lighting setup. 

Let's just say they were totally astonished. They had been looking at what appeared to be a normally lit scene for some time on the monitor at the front of the meeting room, and when they saw for themselves just how low the lighting level was in the room, and the fact that the sources were two iPhones, they were speechless in disbelief.

In order to light the shot with just two iPhones, I set the 75mm Master Prime wide open at T1.3, and the camera at 23.976 fps, ISO 1600, 270-degree shutter angle, and 7000 degrees Kelvin. While it is true that the iPhone is not the best for color balance, I think I made my point.

I had to set my light meter to ISO 3200 to get the minimum reading of f0.7. One of the iPhones functioned as a "key light" and was set at 100% light output; the other iPhone provided back/edge light and I had to reduce its output to 50% because it was too bright. Not kidding.