The new Arri Alexa Mini LF uses the same identical sensor found in the ALEXA LF. This is a 36.7mm x 25.54mm sensor that is slightly larger than the full frame sensor. It is 1.5x larger than the sensor in the ALEXA SXT, and the ALEXA 65 is 1.5x larger than that in the ALEXA LF. To put the sensor size in perspective, Sony’s VENICE uses a 36.2 x 24.1mm sensor. The MONSTRO 8K VV sensor found in RED WEAPON and Panavision Millennium DXL2 uses a 40.96mm x 21.60mm sensor, and ARRI’s ALEXA 65 has an incredible 54.12mm x 25.58mm sensor (active image area).

The A2X sensor of the ALEXA Mini LF is not really new in itself; it is based on two vertical ALEV-III sensors, which are joined together to create a seamless large-format image. This is the same principle as how they created that of the ALEXA 65, which uses three ALEXA sensors that are arranged vertically.

This is only the second camera (if you don’t count the ALEXA 65) that ARRI has launched with a sensor that is capable of recording 4K images without the need for upscaling. The ALEXA Mini LF can record in open gate at a resolution of 4448 x 3096.
3 sensor modes
Like the Sony VENICE aspect ratio independent sensor, the ALEXA Mini LF’s sensor has the ability to be used in three different sensor modes. All features, resolutions and frame rates will be available from launch.

LF Open Door – 36.70 x 25.54 mm with (4448 x 3096) @ 44.71mm image circle. Offers the optimum pixel size of the ALEXA family for the best image quality results in a 4448 x 3096 image.
LF 16: 9 – 31.68 x 1782mm with (3840 x 2160) @ 36.35mm image circle Maximizes lens options while meeting 4K delivery standards. Max 60fps – 20mm Ultra prime will cover for example. Also available as internal scaling to HD at 90fps.
LF 2.39: 1 – 36.70 x 15.31 mm with (4448 x 1856 photo sites) @ 39.76 mm image circle. Combines a cinematic widescreen image with high frame rates up to 60 fps.

All sensor modes offer true 800 ASA sensitivity as well as noise reduction. EI values are between 160-3200.
PL to LPL adapter
Like the ALEXA LF, the ALEXA Mini comes with an LPL lens mount, which is optimized for large-format sensors. The LPL mount features a wider diameter and shorter flange focal depth to accommodate ARRI Signature Prime lenses as well as all future large-format optics. The LPL mount features a larger bore to accommodate the telecentric lens design for the larger sensor. The LPL mount transfers LDS and Cooke/i protocols and is compatible with LDS-2.

The ALEXA Mini LF does not come with a PL-to-LPL adapter, so you can use existing compatible lenses on the new camera. It is an optional extra, but can be rented as part of an ALEXI Mini LF package. The adapter features black flaps, while the LPL mount includes blue flaps. You can set the mount and adapter to 12:00 or 3:00 to match the LDS or /i lens data. The adapter passes the LDS protocol and is compatible with LDS-2.
WiFi
The ALEXA Mini LF has an on-board WiFi radio that provides ALEXA’s wireless web remote control. It can also handle color management. It has a new external WiFi antenna for improved range.
Recording resolutions and media

4.5K in LF Open Gate and LF 2.39: 1
UHD in LF 16: 9
2K 16: 9 with in-camera downscaling in LF 16: 9
HD 16: 9 with in-camera downscaling at LF 16: 9
Provides anamorphic downscaling for lens compression ratios of 1.25x, 1.3x, 1.5x, 2x.

Unlike the ALEXA LF that uses SXR capture units or SxS PRO+ cards, the ALEXA Mini LF records on the new Codex compact units. The drive will be formatted by the ALEXA Mini LF in UDF format for ARRIRAW and ProRes, so both ARRIRAW and ProRes can be recorded on the same media without reformatting or changing drives. ARRI will also use this media for future cameras.

CFast 2.0 cards would not have been fast enough to use with some of the resolutions and frame rates that the Mini LF can record. The SXR capture units were too large and required too much power.
Color management and image processing
The camera is compatible with ARRI Look Files available for SDR, HDR PQ and HDR HLG. ARRI ALEXA LF Mini F provides 16-bit linear in the ALEXA Wide Gamut / Log C color space. You can also get a free color tool from ARRI, its ARRI Color Tool (ACT).