Auto Exposure

Auto exposure automatically sets the amount of light detected by the camera sensor based on settings for light control, exposure compensation, and the day and night exposure times.

Light Control: Sets the mechanism that controls the exposure time of the camera. Light control settings include Digital Exposure and Auto-Iris control.

When Light Control is set to Digital Exposure, the camera controls the exposure time. This setting automatically adjusts the exposure time depending on the light level of the viewed scene, up to the maximum exposure time setting. Digital Exposure is the default setting.

When Light Control is set to Auto-Iris, the lens controls the exposure time. The Auto-Iris exposure times are absolute settings and do not adjust if the scene light level changes.

NOTES:

•Select Digital Exposure if a fixed iris or manual iris lens is used.

•Select Auto-Iris if flickering (a stereoscopic effect or streaking on fast-moving objects) is observed in the scene.

Exposure Compensation: In auto-exposure mode, the user can brighten or darken the image. The camera starts the process by computing an exposure as normal. After the optimal auto exposure is determined, the system applies a manual offset that either causes the final exposure to be brighter or darker. Move the slider to the right to brighten the picture and to the left to darken the image. The exposure compensation range is -100 to 100; the default setting is 0 (zero).

Max Exposure Time (msec): Available only with color cameras, this setting is the maximum time (in milliseconds) that an image is exposed. Increase the exposure time to increase light sensitivity in the scene. The exposure time range is 1 to 500 msec; the default setting is 33.3 msec.

Day Exposure Time (msec): Available only with day/night cameras, this setting is the maximum time (in milliseconds) that an image is exposed during daytime (color) conditions. Decreasing exposure time decreases the light sensitivity of the scene and reduces the streaking of fast moving objects (motion blur); however, it also increases the amount of noise in the scene. The day maximum exposure time range is 1 to 500 msec; the default setting is 33.3 msec.

Night Exposure Time (msec): Available only with day/night cameras, this setting is the maximum time (in milliseconds) that an image is exposed during nighttime (black-white) conditions. Increase the exposure time to increase light sensitivity in the scene. The night maximum exposure time range is 1 to 500 msec; the default setting is 120 msec.

NOTE: Exposure time settings do not affect the image rate setting (refer to Image Rate on page 41).

C2953M-A (5/09)