JVC TK-C215VP12U/E Instructions Manual page 27

Adjusting the brightness
Usually, adjustment of the brightness is not
required. When this is necessary, adjust the iris
level accordingly.
To darken : Anti-clockwise direction (L
side)
To brighten : Clockwise direction (H side)
Memo:
● Do not perform iris level adjustment within 30
seconds after pressing the focus adjustment
button. (It cannot be adjusted correctly as the
electronic shutter mode is activated.)
● Before adjusting the iris level, set the [AGC]
switch of selection switch C to OFF . If
turning too much to L side when not set to
OFF , AGC feature will activate causing the
sensitivity increases and the picture quality
may appear grainy.