The Tiliam Blog

Musing on technologies for video and cinematography

How 8K Measures Up

High Definition is old, 4K is settled in, now it’s the turn of 8K. Asides from professional level cameras, 8K cameras are starting to come to market. One of the most hotly anticipated is the Canon R5 and likely to lead many into the world of 8K video. Is it time to get serious about 8K?

The road to 8K

What resolution is 8K?

Ah, I can see you have some experience in this matter. Good question! Historically, each new resolution has seen multiple variants; HD was 1280×720 or actually 1440×1080 anamorphic or 1920×1080; 4K was 3840×2160 UHD or 4096×2160 DCI. 8K seems to have a clear preference for a single resolution of 7680×3200. It has been chosen for UHDTV-2, DVB UHD-2, Super HiVision and almost all 8K TVs that have been shown to date.

There are a handful of cameras that support 8K video now and several planned. The interesting thing is that most pro cameras support 60 fps out of the box.

All fundamental changes in video content formats have a milestone test broadcast as part of the process of building momentum. The 2020 Tokyo Olympics, now cancelled due to COVID-19, were planned to be broadcast in 8K by NHK’s BS8K satellite TV channel. Expect a milestone broadcast from a major sporting event to be planned as soon as the COVID-19 pandemic ends.

Is 8K “better” than film?

Well, yes and no. It seems that film resolution is somewhere between 4K and 6K depending on who you ask and the size of grain in the film stock you are using for reference. However, film typically has 3 channel colours where digital video from a single sensor uses a colour filter array or chrominance subsampling, or both. Can you get “film look” with 8K? Maybe with colour grading and a 24 fps timeline, but would you add grain in post? To 8K?

Some higher resolution sensors are Quad Bayer, so colour resolution is even more stretched. The quad configuration reduces light spillage from neighbouring pixels that can more easily occur with high resolution sensors.

What can I do to be ready for 8K?

There are some good reasons to move towards 8K: you can capture 8K and downsample to 4K wthout losing quality, your video will be more future proof and you can pull 33 Megapixel stills. Downsides include larger files, slower working in post and finding that the higher resolution reveals deficiencies in your glass.

An in between option might be to capture in 8K, archive your footage, create 4K “proxies”, work with 4K. If you wish to render an 8K timeline you could pull in the 8K footage. The problem with this approach are that you would need a lot of storage, working in raw would probably be impractical, if you do pull in the 8K footage it would need a lot of tweaking.

If your current editing systen struggles with 4K, 8K is four times bigger. It doesn’t necessarily mean all files will be four times larger, but certainly quite a lot bigger than you are working with now. Maybe it would be a good idea to buy, borrow or hire an 8K camera to find out where your workflow has issues so you know what really needs improving and you can be ready when 8K arrives.