Sony FX 6 Quick Start Manual page 114

Cine EI: EI Presets
PRESET SWITCHES
In Cine EI mode, you have to use the Base Low (800 ISO) or Base High
sensitivity (12800 ISO). You cannot change the ISO as you can in
Custom shooting mode.
In Cine EI mode, the L,M and H ISO/GAIN preset switches on the side
of the camera control EI (exposure index) ratings. They do not change
ISO or GAIN. The EI presets control the brightness of the LUT.
You can change these EI preset settings in
Menu/Shooting/ISO/GAIN/EI or by using the direct menu.
The next page describes how you may want to set these presets.