All about the new Alexa SXT

ARRI presented on Friday the latest evolution of its Alexa line of cameras, the SXT, named after “Super Xtended Technology”.

This range will consist of the Alexa SXT EV, SXT Plus and SXT Studio models, which will replace the current XT, except for the Alexa Classic EV, which will remain in the family.

It seems that ARRI wanted to combine the strength and stability of its earlier designs with the color and processing advantages of the latest, creating the new Alexa SXT.

Recording options

One of the qualities most highlighted in the media has been the in-camera recording capability of ProRes 4K, distinguishing between UHD mode (3840×2160) and Cinema mode (4096×2637).

There have been some doubts about how the camera will achieve this resolution, given that the sensor itself does not achieve 4K. Well, the SXT captures 4K in exactly the same way as the Amira does, by performing a small scaling that preserves the fundamental qualities of the image even though the number of pixels is slightly increased. To achieve ProRes UHD, 3.2K of the sensor is used, while to achieve ProRes Cine 4K, 3.4K of the sensor is used, so it always carries the same 1.2x up-sample filter.

Internal features

The new Alexa SXTs retain the 3.4K ALEV III sensor of their predecessors but also borrow high-performance electronics from the Alexa 65. In this way, the latest generation of FPGA processors is combined with a fast motherboard forming the basis for the processing chain, with advanced pixel correction and optional noise reduction.

Like the XTs, these cameras will come with 16:9, 4:3 and Open Gate sensor modes, and can record in both ARRIRAW and ProRes.

There has also been talk that the new architecture could enable hardware upgrades such as a true 4K sensor or even larger, but this is only conjecture.

Advanced color management

They include the color management technology originally designed for the Amira, which allows the creation of new looks.

The ALF-2 (ARRI Look File 2) contains an ASC CDL (Color Decision List) and a 3D LUT. The parameters of both can be combined in-camera on either SDI output or applied to ProRes recordings.

In addition, the preview of looks on set has been improved, allowing for example the support of the Rec color space. 2020.

*Both the ALF-2 file and the tools to generate it are compatible between Alexa SXT, Alexa Mini and Amira.

More connections

These cameras come with three fully independent HD-SDI outputs. This allows, for example, one Log C image to be displayed for the director to view live color-corrected and two other Rec 709 images, with or without overlays, on the other monitors.

The relationship with Codex continues

Codex and ARRI have been working together for some time now to offer their users extensive recording options. Therefore, between the two companies they have already developed the workflow for the new cameras.

The Alexa SXTs incorporate a new Codex recording engine, similar to the system built into the Alexa 65s, and support the latest SXR Capture Drives, which offer a data rate of 20GB/s. The existing XR Capture Drives will also work with the new cameras. To maximize flexibility, the SXTs have a new compartment, developed by Codex, that features adapters for XR and SXR drives and SxS and CFast 2.0 cards.

When will we see them?

The first SXTs are scheduled for release in mid-2015. Those who have purchased an Alexa XT (excepting the XT M) between January 1 and the release of the new models will be able to upgrade the hardware for free to get the Alexa SXT features via the SXR (Super Xtended Recording) module. Still, the company has said that this upgrade “offers all the features of the SXT cameras, though they may not offer the full potential of future upgrades.”