2-10
(1) When the intensity of illumination is high and iris aperture is stopped down, the iris is opened for
compensating drop of the signal level by changing the shutter speed to high (1/250 sec).
(2) Since raising the AGC gain deteriorates the S/N ratio, the E-E level is slightly lowered in the
exposure compensation by controlling the AGC as compared with the iris control mode.
(3) As the intensity of illumination becomes low and AGC gain rises to maximum, the camera enters
the slow shutter mode (1/30 sec).
(4) When the camera enters the slow shutter mode, the signal level rises by 6 dB and the AGC gain
drops in inverse proportion to the signal level.
(5) The auto-light is turned on when the illumination turns down a little more after the camera entered
the slow shutter mode and AGC gain rose to the maximum. There is a hysteresis to prevent
hunting as the auto-light is switched on/off.
(6) The intensity of illumination shown in the figure is just an example and it varies depending on the
object, angle of view, etc.
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