ARRI ALEXA 35 Body & PL Mount Set (LBUS) - Manual (Page 55)

Recording 55
12.4 Starting Recording
The camera supports various ways to start and stop recording. Recording can be started and stopped
by
The REC button on the camera body, the MVF-2 and ARRI hand units such as the WCU-4 and Hi-5
The Camera Companion App
The Remote Switch RS-4, connected to the camera's RS connector
Through WiFi / Ethernet, using the Web Remote or applications communicating via CAP (Camera
Access Protocol)
User button Record Start/Stop supports to start and stop recording.
User buttons can be assigned to e.g. the ARRI Master Grips, the Operator Control Unit OCU-1
and the General Purpose I/O Box
Starting recording returns the MVF-2 as well as the side display to their HOME screen and disables
access to sensor fps, timecode, shutter, exposure index, auto white balance, erase media, playback
and most menu settings.
12.5 Prerecording
Prerecording writes images into an internal ring buffer for up to 20 seconds in real time instead of
recording them directly to the recording medium. When regular recording starts, the buffered images
are written to the recorded clip. This allows unpredictable events to be captured without wasting media
capacity. The maximum available duration of Prerecording is determined by the set combination of
sensor frame rate, recording codec and sensor mode, but can also be set by the user within these
limits.
Prerecording can only be started and stopped using a user button assigned with Prerecording .
► Select MENU > User Buttons and assign Prerecording to the desired button.
► Press the user button to start Prerecording.
► Press the user button again to end Prerecording or press the
REC button to start regular recording.
Info: When ending Prerecording, the ring buffer is cleared.
Info: While Prerecording is active, timecode, shutter, sensor fps, exposure index, auto white
balance, erase media, playback and most menu settings cannot be accessed.
Setting the Prerecording Duration
► Select MENU > Recording > Prerecording max. Duration and set the maximum duration used for
Prerecording in a range from 1 to 20 seconds.
The available Prerecording duration depends on the set Codec, Sensor Mode and Recording
Resolution:
Sensor Mode Recording Resolution Codec Prerec Duration @ 24fps
ARRIRAW 2.8 s
4.6K 3:2
Open Gate
4.6K (4608 x 3164)
Apple ProRes 422 HQ
Apple ProRes 4444
Apple ProRes 4444 XQ
8.5 s
5.6 s
3.6 s