4K Or Not 4K – That Is The Question

A producer’s guide to the pros and cons of shooting in 4K
What is 4K?
Whether a video format is either 'standard' or 'high definition' has always been a moving target. A continual game of leapfrog saw resolutions rise from 35 horizontal scan lines to 100, then from 405 to 625 lines in 1963. The modern era welcomed a standardisation of 625 as the PAL system, but debate soon began over what would constitute the new high definition. Today's definition of HD (1920 x 1080) has been 20 years in development.
Now the next generation of HD is 4K resolution (4096 x 2730), which the CEA is calling Ultra HD is forecast to become the next standard for programme acquisition, delivery and broadcast.
This new VMI article investigates the positives and pitfalls of shooting in 4K and most importantly what you need to know if you want to shoot and produce a programme in 4K.
Why 4K?
Acquisition, post-production and delivery is now fully HD (1920 x 1080) but modern technology now delivers even greater resolutions and 4K has become a practical production format.
There are a number of advantages of adopting 4K acquisition now:
•Enhanced detaila and better overall image quality
•Creative flexibility to zoom and crop in post-production
• Recording in higher-resolution formats will help content retain its value in the longer term
• Keying tools deliver better results due to more well-defined edges
• 3D looks better at higher resolution as seen in projects, such as Avengers 3D
• Major studios hope to attract new audiences into 4K cinemas, which easily outperform HD home theatre systems
• Be prepared! Consumer electronics manufacturers have been disappointed by sales of 3D televisions. Pushing out “Ultra HD”)will be in their interests
Today's Reality
In spite of the clear advantages of acquiring in 4K, very few productions are actually shot in 4K. For most, 4:2:2 or 4:4:4 HD codecs have been good enough for dramas and many features.
The increased camera costs, storage requirements and editing power required by 4K is, at the moment, causing DoPs to hesitate before jumping in... However, there is no doubt that 4K will happen in a big way, very soon.
ARRI
ARRI Alexa. The ARRI Alexa is not a 4K camera but it does have a 3.5K sensor. As well as recording on-board to SxS cards in 1080, its de-bayered RAW output can be recorded on external devicesat 2800 x 2160 - almost 3K. These RAW files offer improved dynamic latitude for excellent highlight control, as well as greatly increased resolution. Skyfall was shot by Roger Deakins using the Arri RAW 2K+ workflow, with the output recorded by a Codex device. Versions were prepared for 4K cinemas with the files simply up-converted and it looked fantastic!
Arri’s official 4K position is that they have made some of the best film cameras yet and film is, in their opinion, still the best acquisition medium for 4K.
Their argument is that if productions want to shoot in 4K, then modern film stocks already facilitate this resolution. As the digital intermediate and telecine post production workflow is very established, producers can continue to shoot and edit film as usual. Because film cameras and stocks are very well established, there is no fear of incompatible or outdated digital standards, as may be the case with new 4K digital formats. Arri's own laser system prints digitally onto film, enabling the highest resolutions to be written back to celluloid: a great way of viewing, publishing and archiving 4K footage.
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