Arri Amira Exposure Guide
While AMIRA’s 14+ stops of exposure latitude and unique highlight handling approaches that of film, there is one major difference between the way film and digital cameras behave: with digital cameras, a change in EI will shift how many stops are available above and below 18% grey – each EI step shifts the location of 18% grey. What is special about AMIRA, however, is that its wide exposure latitude is available at all EI settings.
As a shortcut, Arri have come up with the following method of writing AMIRA’s exposure index:
Values next to the exposure index are the number of stops above and below 18% grey. These values are for Log C. Rec 709 has 0.5 stops fewer in the low end at EI 160, 0.4 stops fewer in the low end at EI 200, and 0.2 stops fewer in the low end at EI 400. Otherwise they are the same.
Exposure Check Options
False colour exposure check
The false color exposure check for the electronic viewfinder and/or LCD display measures the camera image, tints certain signal levels in a distinct color and shows the rest as a black-and-white image. The false color exposure check is based on the color processing set for the respective signal path. You can choose between Log C and Look. Choosing Look/Rec 709, the false color exposure check measurements will be based on the Rec 709 image.
Refer to the chart below to see the default colours as seen on the Amira’s EVF and monitor.
This images shows a slight overexposure in false colour
Zebra exposure tool
As an additional exposure tool, AMIRA includes a powerful zebra function with high and mid zebra, which can be configured in values for range, intensity and color.