Metering With Heat: Shooting “Route 94: My Love” with a Thermal Camera
{Originally posted on www.irvingharvey.com on February 12th, 2014}
In early January, our good friend and director of photography Adam Donald gave us a call and asked for our availability, saying “I have something crazy planned”. He wasn’t kidding. He was recruiting a DIT and camera technician for his upcoming music video shoot with director Ryan Staake. He wasn’t calling us for our experience with RED cameras, or Canon cameras, or Arri cameras, or any other sort of camera we would reasonably be familiar with. Instead, he was calling us to tap on our general technical curiosity and handiness, as he didn’t expect to find anyone familiar with the camera. The camera he was using was the Flir SC8200 — a science-grade thermal imaging camera.
We were immediately excited. Adam was looking for someone to help him figure out how to use the thermal camera and how to translate it, which was built for scientific use, to the requirements of film production. While science is much more concerned with controlled environments and thinking things through than it is about time, film production is all about time. Our challenge was figuring out how to use this camera in a time effective manner. The goal was to work at the same pace (or at least close to the same pace) as we could if we were using a conventional optical camera.
I met up with Adam and his camera crew at Adorama to receive the camera and run tests. We opened the case, and realized that this camera is not built like any camera we recognized. It is essentially a big metal box, which some ports on one end and a small lens on the other. Apparently the lenses aren’t even made out of glass, but are instead made out of some sort of gelatin.
The thermal camera isn’t designed to be moved around quite the same way a film camera is. It is meant to be used while tethered to a Windows laptop over ethernet, connected to Flir’s proprietary software. The camera has no buttons; instead, the software is used to set it up and record. In essence, in this setup the computer is the brains of the camera, while the camera itself is just a sensor. This obviously wouldn’t work in the context of film production, as we couldn’t keep the computer connected to the camera at all times — especially since Adam planned to shoot the entire thing on a steadicam. We did, though, find an alternate way to use the camera. The camera offers an SDI out that is always outputting signal, and we discovered that if we set up the camera with the computer connected to the software, we could unplug the ethernet cable and the settings would stick. We used a Sound Devices PIX 240 ProRes recorder to capture the signal and shot to that.
Beyond the pure technical matters to figure out, we had to learn how to work with the camera in a theoretical sense. Because the camera recorded temperature and not light, we needed to completely rethink the way we understood imaging. Using a camera was no longer about thinking in terms of footcandles or how light passes through the lens and into the sensor. Probably the strangest idea was that heat doesn’t actually look like anything, and the way the camera depicts it is just a representation of the information it records, and as such we could choose how the information was represented. We picked a color scheme for the information (we chose the “Iron” color setting which is reminiscent of how thermal cameras are typically shown). The information was mapped linearly by the camera’s software, using different colors in the scheme to represent different temperatures. The “warmer” colors represented higher temperatures. “Exposing” the camera then became a matter of setting the range of temperature values to be mapped. Setting the low bound essentially set the black point for the video, and setting the high bound set the highlight limits. In order to get the image we were looking for, we manipulated the high and low temperature bounds in order to get the temperature range in the frame where we wanted it.
This also had interesting implications on set. The set itself suddenly became less important, as it was impossible to effectively illuminate it. Because of this, we shot in an empty white cyclorama studio. The music video is primarily set in a club, so we utilized the empty space and colder set to simulate the dark room. This is obvious, but never stopped being mind-bending to me on set — because we weren’t recording light, we didn’t need to worry about it. We didn’t need to use film lights, and we kept the house lights on. Instead of running around with light meters, we found ourselves “metering” with heat; we were thinking about how the various temperatures of things would appear on the camera, and how to add heat in places to craft the image similarly to how we would work with light. We even had a handheld Flir temperature gauge, the kind typically rented from Home Depot to find areas of low insulation in homes, to act as a meter, but we didn’t end up using it much. We didn’t have a grip and electric crew, because we didn’t need one. This meant, hilariously, I didn’t have anyone to go to when I needed power for video village.
As a result of this small crew and gear setup, and the camera being mounted to a steadicam, we were able to move incredibly quickly. We got the cast into position, set up the frame, plugged in the laptop (I was following the camera with the computer and an ethernet cable) and set the temperature range, and shot. We, rather surprisingly, weren’t slowed by the camera at all. Setting the temperature range turned out to be very intuitive, and Adam and I even developed a language to talk about temperature in reference to the image.
One interesting point in the shoot was when we shot a wide shot of the club from a balcony overlooking the dance floor. We didn’t have enough extras to completely fill in the crowd, so we instead planned to shoot the crowd in sections and composite them together, similar to how the DC reflecting pool crowd shot in Forrest Gump was created. Because we were working in terms of heat, we were able to use the cold floor as a luma drop and key out the black (as the subjects were much brighter).
The shoot went unbelievably well, considering that this is the first time we had ever used this technology. We found ourselves constantly amazed by what heat actually does, and I think that sentiment is reflected in how we shot the video. The shoot ended up being a ton of fun. Congrats to Adam and Ryan for conceiving such an awesome idea and creating such an awesome video! Check out the final product below:
Written by Matthew Greenberg, Colorist & Technical Supervisor.
