ARRI Alexa XT 4K Anamorphic Workflow

As online 4K/UHD distribution/exhibition and 4K digital cinema projection rapidly expand, it’s important that content creators prepare to get their work-flow optimized for exhibition platforms.

Today filmmakers are empowered by incredible tools, which can help them get the best out of their acquisition camera system. However, as Arri have yet to release a 4K sensor camera, how can Alexa  users take advantage of a developing 4K eco-system without a 4K camera?

Light Iron’s CEO Michael Cioni talks about how ARRI Alexa users can get the most out of a 3K sensor and creatively integrate it into a 4K world. With this unique workflow, Alexa XT 4:3 users can get the most out of the ARRI Alexa’s 3K sensor for UHD applications.

Arri Alexa 4K Anamorphic Workflow from Light Iron on Vimeo.

US based post-production company Light Iron has produced many 4K DCP Masters for Hollywood movies such as David Fincher’s “Social Network”,  “The Girl With A Dragon Tatoo”, “Hitchcock”, “The Muppets”, “The World Made Straight” and many others.

According to Michael Cioni in the near future “editing in 3K or 4K is going to be a big deal”.  He also predicts that the fastest transition to 4K is going to happen online with the expansion and improvement of broadband connectivity. Cioni also shared an interesting statistic that 78% of adults in the US have watched their favourite shows online in 2013. 80% percent of cinema content nowadays is shot in 3K+ resolutions.


However, 99% is still delivered in 2K. The 3 big reasons against delivering cinema in 4K according to Cioni are the expensive 4K VFX workflow, the lack of post infrastructure and at last, but not at least, the conservative and uneducated users who still aggressively support the 2K delivering workflow.

He offers an interesting workflow decision for taking maximum advantage of Arri Alexa XT4:3 cameras that has the ability to shoot raw in 3K resolution.


According to him the best way to deliver the highest possible quality picture from the Arri Alexa is to shoot Arri RAW internally (on the Alexa XT 4:3 models) at the highest possible resolution with Anamorphic lenses.

Afterwords, he suggests to transcode the .ARI files to ProRes 4444 Log Files in order to maintain the best possible quality and keep the most cost-effectiveness at the same time. The 2880x2160p resolution of the Alexa XT gives us around 280 GB per hour in ProRes 4444 that is 2 times less than the hard disk space we need for the original 3K Arri RAW files in the same resolution.

Those ProRes 4444  files equal 6.2 Megapixels of resolution that is as close as possible to the  7 Megapixels 4K DCI resolution requirements.

Arri Alexa ProRes 4444 MBP

Content creators can use this workflow with other cameras such as the Blackmagic Cinema Camera, which shoots 2.5K Raw in order to deliver great looking 4K DCPs, despite the fact the native camera resolutions is less than the delivery resolution of 4K.

Whether you deliver in HD, 2K or 4K  it is always  better to shoot in the highest possible resolution with the highest possible quality that your camera gives you and later transcode into other more efficient and friendly-editable format in order to optimize your work-flow for delivery.

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