ARRI Alexa Mini Sensor Modes

A comparison of the sensor mode options available in the ARRI Alexa Mini camera, including image circles and maximum frame rates.

Ben Bateman

Updated August 25, 2022

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3 min read

When looking at the different sensor modes available in the ARRI Alexa Mini camera, it's important to know that the sensor mode you choose determines things like:

  1. The image circle required from a lens to cover the sensor area without portholing or vignetting.
  2. The angle of view of a given lens.
  3. The maximum frame rate you can select.
  4. The pixel resolution of recorded clips.

The Sensor Mode Determines The Effective Sensor Size

Essentially, the sensor mode you choose determines the area/size of the sensor you are using. In Open Gate 3.4K mode, you are using the entire camera sensor. In other modes, you are using a sub-section of the physical sensor.

How Do I Change The Sensor Mode?

The sensor mode is determined by two factors:

  1. The codec you want to record in - ARRIRAW or ProRes.
  2. Recording resolution. Set this in the recording menu after deciding which codec you want to record in, as the codec determines which options are available in this menu.
Setting the recording resolution in the recording menu.

Setting the recording resolution in the recording menu.

Read on for a visualisation of the Alexa Mini sensor modes and a tabular summary of the maximum frame rates available in each mode.

Visualising The Sensor Modes

Below is an interactive depiction of the different sensor modes and how much of the sensor they use. You can also see the image circle required to cover each mode.

Alexa Mini sensor modes. Hover over a mode, or click/tap it to see a summary of the mode.

Recording Resolution, Codec and Maximum Frame Rate

Here's a summary of the resolution options. For each option you can see the codec and maximum frame rate available.

Arri Alexa Mini Sensor Mode Comparison
Sensor Mode Clip Resolution Codecs Max FPS

Open Gate 3.4K

3424 x 2202

ARRIRAW

30

ARRIRAW 16:9 2.8K

2880 x 1620

ARRIRAW

48

2.39:1 2K Anamorphic

2048 x 858

ProRes

120

4:3 2.8K

2880 x 2880

ProRes

50

4K UHD

3840 x 2160

ProRes

60

3.2K

3200 x 1800

ProRes

60

2K

2048 x 1152

ProRes

200

HD

1920 x 1080

ProRes

200

HD Anamorphic

1920 x 1080

ProRes

120

S16 HD

1920 x 1080

ProRes

200

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