ARRI ALEXA Mini LF Ready to Shoot V-Mount Set (LPL) - Manual (Page 61)

Look Settings 61
15.1 Processing and Color Spaces
Log C
The Log C curve is a logarithmic encoding of the scene, meaning that the relation between exposure
measured in stops and the signal is constant over a wide range. Each stop of exposure increases the
signal by the same amount. The overall shape of the Log C curve is similar to the exposure curves of
film negatives. Because of fundamental differences between a sensor and negative film, however, the
color characteristics remain different.
Log C actually is a set of curves for different EI values/ASA ratings. Each curve maps the sensor signal,
corresponding to 18% gray scene luminance, to a code value of 400 in a 10 bit signal. A 10 bit signal
offers a total code value range of 0 to 1023. The maximum value of the Log C curve depends on the
set EI value. The reason is quite simple: When the lens is stopped down, by one stop for example
and the EI setting is increased from, say, 800 to 1600, the sensor will capture one stop more highlight
information. Since the Log C output represents scene exposure values, the maximum value increases.
Configuration of EVF/Mon. and SDI Processing
1. Select
MENU > Look > EVF/Mon. Processing .
MENU > Look > SDI 1 Processing .
MENU > Look > SDI 2 Processing .
Following processing options are available:
Log C Based on the Cineon format for output to film print or digital intermediate, this
logarithmic processing requires color grading in postproduction. On standard
broadcast monitors, Log C images appear flat and desaturated. Proper dis-
play, dailies and editing proxies require a conversion look-up table (LUT).
Look Select to apply the look set in MENU > Look > Look to the output path.
Applies a video display processing to camera images. The default ARRI 709
look complies with the ITU.R-BT709 standard for display on standard broad-
cast monitors.
ALEXA Classic
709
Creates a Rec 709 equivalent image in the same way that it is processed in
the ALEXA Classic product line. This setting may be used when the selected
Look file alters the image too drastically, but a Log C image would be too flat
for monitoring.
2. Select the desired processing for each output.
The currently set processing is displayed in the status info of EVF/Mon. and SDI outs.
Configuration of SDI Color Space
1. Select
MENU > Look > SDI 1 Color Space .
MENU > Look > SDI 2 Color Space .
The color space options for the SDI outputs are: