Sony MVS-8000X System User Manual page 1045

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In the <Fader Curve> group, select the fader lever operation mode.
Normal: The transition progress is linear, according to the fader lever
position. (Factory default setting)
Adv Tally Mode: When the fader lever is moved from the end of its travel,
the tally is output slightly before the transition starts.
Settings Relating to Video Switching (Transition Menu)
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