Philips VCM8175/00T - Manual (Page 10)

The given sensitivities are valid for a common lens transmission of 80%
and a scene reflection of 75%. In case of an auto-Iris lens the maximum
illumination level is far more than 100,000 lux (direct sunlight). The
apperture of the lens will automatically close when used in a high-light
environment.
Automatic iris lenses:
Note: When the camera is used outdoors for longer periods of time
(high-light environments) the use of auto-iris lenses is recommended.
The aperture of a passive auto-iris lens is DC-controlled via the
4-pole auto-iris connector at the back of the camera (fig. A-11).
The pin connections of this auto-iris connector is:
pin 1 = control coil -
pin 2 = control coil +
pin 3 = driving coil +
pin 4 = driving coil -
The auto-iris lens cable should be provided with a 4-pole plug to
match. Recommended lens cable plugs are:
Chuomusen type E4-191J-100 or E4-151J
Changing lenses: Remove the old lens by turning it counter-clockwise.
While unscrewing the lens you should not release the back-focus
locking ring (fig. A-9) otherwise you may have to readjust the
back-focus of the camera.
Mount the lens by turning it clockwise onto the lens mount of the
camera. In case of a C-mount lens you first need to mount a 5mm
spacer (C/CS adapter ring).
When an auto-iris lens is mounted, connect the lens cable to the
auto-iris connector at the back of the camera (fig. A-11).
Point the camera at the object to be monitored and adjust the manual
focus of the lens (if present) for an optimal image sharpness.