EL-2800M-USB / EL-2800C-USB
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8.8 ALC
In the EL-2800M-USB and EL-2800C-USB, auto gain, auto shutter and auto iris functions can be
combined to provide a wide ranging automatic exposure control from dark to bright or vice versa.
The functions are applied in the sequence shown below and if one function is disabled, the linkage
between the other two is maintained.
In order to make the ALC function effective, set the Auto Iris Lens Control Signal Output to “ON”.
The auto iris function works together with AGC and Exposure Auto.
If the lighting condition is changed from bright to dark AIC ― ASC ― AGC
If the lighting condition is changed from dark to bright AGC ― ASC ― AIC
Fig.48 ALC function concept
ALC Reference will determine the target video level for AGC, Auto Shutter and/or Auto iris. For
instance, if ALC Reference is set to 100% video level, AGC, Auto Shutter and/or Auto iris will
function to maintain 100% video level.
Please note that ALC function is available only in continuous mode, as well as RCT mode.
Gain is fixed at Min.
Dark
Light changes
Bright
Auto Shutter
Max
Auto shutter operation
Max
～
Min (User set)
Auto Shutter
fixed at Min
Iris diaphragm fixed (Open)
Auto iris
operation
AGC works:
Auto shutter works:
Auto iris works:
AGC operation
Max
～
Min (User set)
AGC
Max
Iris stops just
before close
Operation if light changes
from dark to bright
Operation if light changes
from bright to dark
