Why do this relative handful of directors continue to insist on shooting film? There are two primary reasons:
- Film can capture a bigger range of colors than digital camera--the equivalent of 16 bits of resolution. By comparison, Arri's Alexa, the most popular camera for high-end cinematography, captures color information with 15 bits of resolution, but then may lose bits of resolution when it converts the video to a color space for editing and viewing.
- Under ideal conditions, 35mm film has an image resolution of around 5300 x 4000 pixels, while the Digital Cinema standard for 4K acquisition and projection is 4096 x 2160 pixels. However, many movie theaters are still using 2K projectors, which limits the resolution to 2048 x 1080. Compared to either digital standard, film (hypothetically, at least) provides far more image detail.
So, those directors who still want to use film have a solid rationale for doing so, even if most of the increased resolution and color space are lost once they're projected on digital projectors or watched on HD, or even Ultra HD TVs. However, the vast majority of directors and cinematographers have switched to digital for several reasons:
- Digital cameras have dramatically more dynamic range (the ability to capture bright and dark subjects at the same time) than does film. Typically, the dynamic range of movie film is 1,000: 1 (approximately 10 bits or 10 f-stops.) Even video cameras costing a few thousand dollars can capture 10 f-stops or more, and the Arri Alexa has a range of more than 14 f-stops, or better than 16,384:1.
- Digital media is much less expensive than film over time, because it can be reused. Movie productions typically offload recorded flash media to hard and flash drives during the day, then erase and reuse the flash media. Digital's much lower costs also enable directors to get coverage from a variety of angles and framings.
- 35mm film magazines usually only allow a maximum of 1000 feet of film to be loaded, due to size and weight. That means that magazines have to be changed every 11 minutes of filming (at 24 frames per second.) Depending on the image resolution, dynamic range and color depth, a single piece of digital flash media can hold hours of video. That allows for long continuous shots and far fewer interruptions to change media.
- Digital cameras have an enormous range of sizes and weights, many of which are smaller and lighter than any practical motion picture film camera can be. This gives filmmakers enormous flexibility for shooting in tight quarters and in sports and action situations. It also makes lightweight drones feasible for shooting, where previously only helicopters and airplanes were viable platforms for aerial photography.
- Specialized digital cameras can provide much higher frame rates than are either economically or technically feasible for film cameras. For example, Vision Research's Phantom Flex4K digital camera can shoot Digital Cinema 4K at 1,000 frames per second, or 2K at 1,950 frames per second. By comparison, film cameras usually shoot 24 frames per second.
There's a technology coming down the pike that's likely to make film obsolete, even for the directors who still insist on using it. I wrote about High Dynamic Range (HDR) video two weeks ago, and I won't repeat all the arguments I made in that post. Here's a summary of HDR's advantages:
- Much greater dynamic range; Dolby says that its Dolby Vision HDR system will have as much as a 200,000:1 dynamic range. Many current digital cinema cameras can be adapted to shoot HDR video when there are commercially-available ways to view it.
- Color spaces that are as big or bigger than motion picture film.
However, there are several problems with HDR, beyond what I stated in my post:
- There are no current theater projectors, film or digital, that can project HDR images. Film is only capable of 1,000:1 dynamic range, and film can't project a true black because even the blackest part of an image can't block all the light from the powerful xenon bulb in film projectors. Digital projectors use a similar xenon light and have the same problem. It's possible that laser-based digital projectors could project both the dynamic range and color space of HDR, but to my knowledge it hasn't been demonstrated yet.
- With the exception of the handful of expensive professional Organic LED (OLED) displays in use, today's current HDTVs can't provide either the dynanic range or color space of HDR. However, LCD HD and Ultra HD TVs can be engineered to have a separate LED backlight for every pixel, and most LCD displays are capable of displaying a bigger color space than is currently used. Dolby, Technicolor, Philips and the BBC are all either in talks with or have already licensed technology to consumer electronics manufacturers to implement their HDR formats in future HD and Ultra HD TVs.
I believe that when the aforementioned film-holdout directors see HDR, they're going to want to use it--and that's when film dies, once and for all, for movie production. (Film is already dead in movie theaters, despite some last-gasp attempts to keep it viable.) The problem, of course, is that there's no easy way to implement HDR in movie theaters. However, as I wrote in my previous post, if past experience is a guide, it make take as long as ten years for HDR to become standardized and available to consumers at an affordable price. That will give theater operators and digital projector companies time to figure out a way to make HDR work in theaters.