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 25 Aug 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:
- The image circle required from a lens to cover the sensor area without portholing or vignetting.
- The angle of view of a given lens.
- The maximum frame rate you can select.
- 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:
- The codec you want to record in - ARRIRAW or ProRes.
- 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.
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.
| 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 |
