By John Klein
Odds are, as an indie filmmaker, the resolution of your image will be one of the first decisions you make. Whether it’s determined by your budget, the equipment you have access to, a creative or pragmatic choice based on the project, or by the final distribution platform, it’s a decision that affects every part of the filmmaking process.
4K and UHD have become more ubiquitous, and the streaming capabilities of platforms like Netflix, YouTube, and Hulu demand more compliance on the 4K front. But it can be a little daunting to figure out exactly what’s meant by 4K, or what changes your aspect ratio may invite to your resolution and what that means going forward for, say, theatrical versus online release. What do you need to know? What do you need to ask yourself before making the decision?
First of all, let’s define resolution. Simply put, it’s the number of pixels tall (vertical lines) by the number of pixels wide (horizontal lines) your image entails, i.e. 1920×1080, commonly referred to as 1080p. Standard definition images – a rarity now, but common on old analog TVs and mini DV tapes from the early days of digital – would typically have a resolution of 640 pixels wide by 480 pixels tall, with an aspect ratio of 4:3. When 16:9 became a more standard aspect ratio, that resolution would shift to 720×480, or 480p.
Nowadays, however, we’re at a transition point between the world of high definition (HD) and ultra-high definition (UHD or 4K). Most people still own their HD TVs, which are typically either 1280×720 (720p) or 1080p, and several indie production companies and filmmakers still use cameras like Canon’s DSLRs or the C100 and C300 for their documentary or videography work. However, the rapid rise of 4K TVs and cameras means that, for a standard 16:9 TV, you’re looking at a resolution of 3840×2160, or 2160p.
Yet, again, that still doesn’t tell the whole story. Technically, that’s the resolution for 4K UHD, but not for 4K DCI, which traditionally denotes a 4096×2160 resolution and an aspect ratio of 1.9:1, and which might be confusing because the term “4K” here refers to the horizontal resolution, not the vertical resolution as with other formats like 1080p. And what of cameras like the ARRI Alexa or the Panasonic GH5, which have a 4:3 sensor but record in several different flavors of 4K? The RED line of cameras offers a variety of resolutions depending on your aspect ratio; in addition, the RED Dragon goes up to 6K and the Epic-W goes all the way up to 8K! And even in the HD realm, there’s a difference between standard 1080 and what’s referred to as 2K.
As a filmmaker, you’ll have to determine what kind of project you’re making and how you want it to be viewed. If it’s for a theatrical release, as crazy as it sounds, 4K may not be necessary; most theaters screen 2K DCP files with a resolution of either 1998×1080 or 2048×1152, tailored to fit whatever aspect ratio you delivered. And if the intended viewing platform is, say, a smartphone or a smaller tablet, your audience won’t see the extra sharpness benefits of 4K.
These examples are due to a basic principle: more pixels make for a clearer image, but that depends on both (a) the size of the screen and (b) the viewing distance. I can watch a standard definition video on my phone from a couple feet away, and it could potentially appear clearer and sharper to my eyes than a high definition video on a 55” screen from the same distance. In the latter case, I’d probably be able to see the square pixels that make up the image. With theatrical releases, even given the large screen size, typically we sit as much as 50 feet away from the screen, so 2K is plenty sharp for our eyes.
Of course, a larger resolution can help with overall sharpness, visual effects, and with various kinds of exports down the line. Netflix, as said above, requires 4K delivery of all its shows and films, and will only accept films shot on certain cameras. YouTube and Vimeo have 4K options for streaming, useful on the Retina displays of Apple computers. And if you bought a 60” UHD screen for your home, I’d wager that you’ll benefit a lot from films shot in 4K!
At the end of the day, 4K has become so easily achievable thanks to the onslaught of mirrorless cameras such as the Sony A7s and the Panasonic GH5, low-cost prosumer options such as the Black Magic Ursa lineup, and the old stalwarts such as the FS7 and C300 Mark II alongside the new guard such as the Panasonic EVA-1. And hard drives are crazy cheap to boot. There’s no real reason to avoid filming in the higher resolutions. But your VFX budget may not allow you to deliver 4K files to match, and your delivery options may not require a 4K master; some clients won’t even be able to view those files on their system. Ask up front, plan for it down the line, and you’ll be set.