Sony BVF-55 Operation Manual page 18

Functions of parts and controls
9 Tilt knob
Adjusts the tilt friction.
0 UP TALLY switch
When this switch is set to ON, the UP TALLY lamp
lights in the same way as the R tally lamp.
qa UP TALLY DIMMER control
Adjusts the brightness of the UP TALLY lamp.
4(GB)
9
q;
qa