ARRI ALEXA Mini User Manual

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13.9.1 EI technical details
The Exposure Index (EI) is the applied sensitivity of the camera. The ALEXA Mini
has a base sensitivity of 800 ASA. This means that the dynamic range is almost
evenly distributed above and below neutral gray with low noise in the shadows and
clean, smooth clipping behavior in the highlights. Due to its high dynamic range, the
ALEXA Mini's sensitivity can be set from 160 to 3200 ASA in steps of 1/3 stops while
maintaining high image quality:
Applying the exposure indexes at the extremes of the range will nonetheless have an
influence on the images.
At low exposure indexes, such as 160 ASA, the dynamic range below neutral gray
increases, reducing noise even further. At the same time, the dynamic range above
neutral gray is slightly reduced.
Highlight clipping itself is not influenced by this, but the shoulder of the gamma
curve will get slightly steeper, reducing the smoothness of the change from almost
overexposed to overexposed.
At high exposure indexes, such as 1600 ASA, the images behave in the opposite way.
Noise is increased, which makes it important to judge shadow detail, while there will
be even more headroom in the highlights:

ARRI ALEXA Mini Specifications

General

Sensor Type	ALEV III CMOS
Dynamic Range	14+ stops
Recording Formats	ARRIRAW, ProRes
Power Input	10.5-34 V DC
Base Sensitivity	EI 800
Lens Mount	PL mount
Weight	2.3 kg
ISO Range	160 to 3200
Frame Rates	0.75 - 200 fps (depending on recording format and sensor mode)
Dimensions	185 mm x 125 mm x 140 mm
Power Consumption	Approx. 50 W
Outputs	HD-SDI
Sensor Size	Super 35 format