20
Use a Neutral Density filter or an Infra-Red Pass filter to
cover the lens during focusing to simulate low light
conditions on scene for correct 24-hour focusing. For vari-
focal lenses, the camera should be focused with the lens
iris fully opened to simulate the worst possible depth of
field. Using a Neutral Density filter or Infra-Red Pass filter
will ensure the iris is fully open for correct setup and
adjustment.
Note that statement above is applicable only for Day/Night
or IR version cameras.