Axis 2120 User Manual page 43

AXIS 2120 User's Manual
Exposure Control Overview
The table below provides a summary of the Exposure Control settings in the Image -
Advanced page. Select the parameters appropriate to your lens type and product
application:
Lens Options
DC Iris
Non DC Iris - Manual
Non DC Iris - Shutter
Non DC Iris - Auto
Other Advanced Parameters
Lens Options
Shutter Speed
Sharpness
Gain
ALC Level
Description
The AXIS 2120 is supplied with a DC Iris lens as standard; consequently, the DC Iris setting is the
standard factory default setting within the Image-Advanced page. It allows the user to manually
specify the exposure, shutter speed, gain, and ALC levels.
Choose this setting if you have fitted a non-DC Iris lens to your AXIS 2120, but wish to adjust the
shutter speed and gain manually.
Choose this setting if you have fitted a non-DC Iris lens to your AXIS 2120, but wish to adjust the
shutter speed,manually.
Choose this setting if you have fitted a non-DC Iris lens to your AXIS 2120 and would like the shutter
speed and gain to be adjusted automatically.
Description
Derived from the shutter speed on a normal camera, this parameter defines the exposure period for
each image. Use a high shutter speed only if your image subject is expected to be moving quickly;
otherwise, a slower speed will normally suffice.
Defines a level of differentiation between light and dark areas in the image. Corresponding higher
levels of sharpness provide for sharper images, but also cause the image compression to be more
complex. Consequently, the file size of a sharp image can be significantly greater than for an image
that is less sharp.
Adjust the gain to suit the average level of light at your point of installation. The AXIS 2120 should
be set to a corresponding higher level of Gain if your camera is normally monitoring an area at
night, or is sited in a dark room or cupboard.
This defines how acutely the lens reacts to a single light source within the image. For example, with
the ALC level set to a lower level, the headlights from a car will generally cause the calculated aver-
age level of light to increase, and subsequently result in a compensated image that is usually much
darker.
Adjusting the ALC to a higher level reduces the sensitivity of the lens to single light sources within
the image.
Adjusting the Camera Focus
43