Software User’s Manual Ver.A1D-502-V8.03.30-NB
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Exposure Mode - Auto
In Auto Exposure Mode, you control the image brightness by configuring the AE
Reference Target and Slowest Auto Shutter.
AE Reference Target (Auto Exposure reference target) can be considered as the
“
Target Brightness on Sensor
”
. The camera will use several internal parameters to
achieve best quality with reference to this. The higher this value, the brighter
the overall scene, however, there may be more noise at night in such case.
The range of AE Reference Target is 1~255.
The camera will automatically control shutter speed, auto iris (if available) and
signal gain to achieve the target level set by the user. If the auto iris does not exist
or is already opened to a maximum size, and the image is still darker than the
user defined target, it will further slow down the shutter speed within the allowed
range (set by user under Slowest Auto Shutter Speed) and increase the signal
gain.
Slowest Auto Shutter Speed is the user defined threshold for slowest allowed speed
of auto shutter. For example, if by default the shutter speed would vary between
1/5s ~ 1/2000s depending on the lighting conditions, then setting the Slowest
Auto Shutter Speed to 1/30s would narrow down the auto shutter range to work
between 1/30s ~ 1/2000s. The purpose of allowing user to define the threshold
for slowest speed is to avoid motion blur caused by too slow shutter at night.
It is also important to know that very high shutter speed is not recommended for
indoor solutions with artificial light that flashes with certain frequency, as it may
produce flickering effect, regardless of Exposure mode.
In extreme low light conditions, the shutter speed is slown down to get more light
into one image, but not slower than the user defined threshold.