Large format cinematography is in high demand in today’s cinema production landscape. In Part One of our look at this growing field, Adam Hamer looks at the sensors and lenses that are powering it.
Large format camera systems utilize an imaging sensor which is larger than the traditional cinematic imaging plane of super 35, or Academy Standard 3 perf motion picture film. The large format imaging systems in use today range from full frame (35mm still film), VistaVision, all the way up to 5 perf 65mm film (Alexa 65 is the digital equivalent) and topping out at a whopping 70mm negative for IMAX feature films. As futureproof systems capable of creating eye-popping imagery, the rebirth of large format cinema will continue to see a resurgence and a spike in market share. Feeding a constant desire to create larger scale and finer quality imagery, top content producers are seeking out the look created by utilizing a camera with a large active imaging area.
The sensor technology for large format cinematography is dominated currently by three digital cinematography platforms (soon to be four, with Sony’s recent Cine Gear 2017 announcement that it is developing a full frame cinema camera): ARRI's Alexa 65, RED's 8k VistaVision Weapon, and Panavision's DXL powered by RED’s 8K VV Sensor with custom color science and OLPF engineering by Light Iron. These sensors vary in physical size from the 40.96 x 21.6mm of the RED VV sensor to the absolutely massive 51.12 x 25.88mm size of the Alexa 65 sensor. Such large sensors allow for an absolutely stunning pixel pitch to be maintained while simultaneously capturing incredibly high-resolution video. Pixel pitch refers to a sensor’s overall pixel size, which affects the system’s sensitivity to light, playing a pivotal role in determining overall image quality. The more light-responsive a sensor is, the more accurately it can render and define minute shadow detail and highlight roll off.
Analyzing the list of cameras used on the Sundance film festival selections this year, an interesting trend is observed. More films are being captured at least partially (B Cam unit), with the Sony A7S camera, a compact mirrorless system sold primarily as a consumer product. Why would a small form factor, mirrorless sensor camera be desirable for cinematic performance at such a high technical level? Amongst other factors, it is one of the only large sensor (full frame) cameras that shoots native 4k video.
The influence of the A7S in terms of festival presence and industry adoption shows that the power of full frame cinema imaging should not be underestimated. It should be noted that although the A7S is a high-performing, large format camera, it only records color in 8-bit depth. While 8-bit is sufficient for the majority of monitoring systems today, it is not ideal for FX work or advanced color mastering, thereby creating a vast difference in technical ability between the A7S and a more traditional cinema camera. Not only are independent content creators flocking to the A7S for feature usage, but also the studios as well. Screen Gems has recently publicized its intent to shoot many of its upcoming horror feature films on the A7S. This is a testament to the widespread adoption of large format sensor tech.
Why is a larger imaging system more desirable? For one, the format's ability to recreate spatial reality with physics that more closely represent the optics of the eye. Another significant reason is projection size. Randy Wedick, Head Technical Consultant at Band Pro Film and Digital, comments on the nature of image size in relation to the final, projected result. The magnification required to project large format negatives to a screen is far less than with a smaller imaging system. The lower magnification ratio affects image quality for the better, creating finer pictures and less overall grain. If the magnification is decreased, signal to noise ratio is correspondingly increased, resulting in a cleaner master file and print for public exhibition and archiving.