Download ARRI ALEXA SUP 11.1 Pocket Guide

Working with ALEXA
Metadata Overview
Metadata is a set of data that describes and gives
information about other data (sometimes called the
'essence'). ALEXA and ALEXA XT always records as
much metadata as is available. This additional information makes documentation easier as the metadata
is stored within the image files so it cannot get lost.
A range of automatic and human-readable data is
being delivered by the ALEXA camera; this data
makes work in post much easier: knowing exposure
index, gamma and white balance information, for
example, is essential for creating dailies or color
grading. Reel number, project fps, date and time
become important when combining images and
sound from different sources.
Metadata in the ALEXA appears in several different
ways: embedded in the ARRIRAW header, QuickTime
metadata atom and ARRI Digital Meta Data (ADMD)
atom, MXF metadata XML, Final Cut Pro 7 XML and
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Avid Log Exchange (ALE) file. These atoms or text
based files can be parsed by e.g. editing software
and offer the accompanying information mentioned
above to the application and its user.
For more information on the metadata have a look at
our whitepaper at www.arri.com/alexa/downloads.
Lens Data System
By combining the ALEXA XT Series, ALEXA Plus,
ALEXA M or ALEXA Studio camera with lenses
equipped with a Lens Data System (LDS) PL-Mount
additional frame by frame lens metadata for use in
VFX work will be acquired. When using a non-LDS
lens in combination with the ARRI Controlled Lens
Motors a profile for the lens can be created within
the Lens Data Archive (LDA); by doing so the ALEXA
camera can compensate for the missing sensors
inside the lens by reading the motor’s position and
calculating the current focus, iris or zoom value.
A guide on how to create an entry for an unknown
lens can be found on page 62.