Vivotek SD9361-EHL User Manual page 56

VIVOTEK
Exposure control:
■ Exposure level: You can manually set the Exposure level, which ranges from -2.0 to +2.0 (dark
to bright). You can also select other values from the Exposure mode menus and select a preferred
scenario or manually configure the associated settings. You may prefer a shorter shutter time to better
capture moving objects, while a faster shutter reduces light and needs to be compensated by electrical
brightness gains.
■ Exposure mode:
Select Auto, Shutter Priority, Iris Priority, or Manual mode according to your needs.
- Auto: System default, which automatically adjusts the iris, shutter speed, and gain for an optimmal
exposure level.
- Shutter Priority: When selected, the Exposure time slide bar will appear, allowing you to select an
exposure time ranging from 1/10,000, to 1/1 second. Once a fixed value is selected, system firmware
will automatically tune the gain and iris settings to match an optimal exposure level.
- Iris Priority: When selected, the Iris adjustment slide bar will appear, allowing you to select
an aperture size ranging from F14 to F1.6. Once a fixed value is selected, system firmware will
automatically tune the gain and exposure time to match an optimal exposure level. The value is
measured in the F-number as the ratio of the focal length to the lens diameter. Iris size is inversely
proportional to the F-number; therefore, the smaller the F-number, the greater is the exposure ratio.
Smaller F-number (larger exposure ratio, largest size of lens aperture opening) is shown on the right of
the slide bar.
- Manual: Select Manual to set a fixed exposure time, iris, and gain. Then, tune the slide bar to set the
Exposure time, Iris adjustment, and Gain Control to the best image quality. A shorter exposure time
allows less amount of light to enter the sensor; while a higher gain control value generates certain
amount of noises.
Note the following when the Manual mode is selected:
1. The Exposure level bar will not be available.
2. The IR cut filter setting will switch to Day Mode. If it was previously configured into other modes,
the previous setting remains intact.
Manual: Note that WDR and Defog functions will be disabled using the Manual mode setting.
NOTE:
• When Iris Priority is selected for the Exposure mode, the tunable aperture size is related to zoom
ratio. When using different zoom ratios, the range of aperture sizes can be different. When zoom ratio is
0x, the range of iris sizes is F1.6~F14. When zoom ratio is 20x, the iris size is F3.4.
56 - User's Manual