Here’s an excerpt from an interview with cinematographer Powell Robinson published by PostPerspective, focusing on the DP’s dynamic use of ISO with the ARRI Alexa Mini. We found it interesting because over the years, some cinematographers have claimed that shooting at low ISOs on an Alexa hurts dynamic range in the highlights and produces digital-looking, sterile images and that changing ISO from scene to scene can result in jarring changes in texture:
“The trouble with low ISO ratings on the Alexa is that the loss of extended overexposure detail when combined with the hyper clean image tends to make everything feel more digital…”
“[C]onsistency of exposure and noise within every shot in a sequence matters in narrative fiction…”
Powell Robinson:
“Earlier that year, I’d shot a few projects on film (16mm and 35mm), and a lot of our reference films were also shot on film, so I decided to rate the camera at 500 ISO for 85% of the interiors on the shoot. There were some daytime interior scenes where we lost power, so I had to go with 800 to maximize available light. And for others, where curtains were open and we were getting extreme highlights, I went up to 800 or 1000 to preserve that upper-range info.”
“The main benefits to doing 500 ISO interior/night shoots when working with a non-dual-native ISO camera like the Alexa Mini classic are that you get cleaner shadow information and more control over your contrast ratio/ambient light. The higher the ISO, the more ambient light will affect your image — so on tiny practical sets like ours with a lot of uncontrollable bounce, this was really helpful.”
“Also, less sensor noise going into post means less accentuated colored noise when you start applying a strong film emulation or an aggressive grade. You also have total control over how much noise/texture the image has by applying additional post film grain or leaving it clean. When you light as soft-key but high-contrast as I do, those qualities are vital to keeping a pleasing fill-side that doesn’t look gnarly when projected on a large screen — silhouettes or an underexposed fill-side skin tone don’t just turn to noise/mess.”
The Daejeon Chronicles 
Leave a Reply