Hitachi HV-D25 用户手册
33
How to Attain Better Images
Black Balance Adjustment
Adjust black balance to provide proper color tone at a dark part of video image. In the following cases, be sure to carry
out black balance adjustment.
•
When using the camera first after purchasing it.
•
When using the camera after it has been unused for a long time.
•
Wen the camera operating environment is changed (e.g., when the ambient temperature varies significantly).
Under normal condition, it is not required to make black balance adjustment at power-on.
1. In the Direct mode, hold the ABB button pressed for about 2 seconds for automatic black balance adjustment. With
MESSAGE RTN:ON, AUTO BLACK appears. At the end of successful adjustment AUTO BLACK:OK appears.
(Notes)
1) Where the lens having the auto iris function is used, the iris is closed automatically during adjustment.
Sometimes occurs when adjusted with the lens iris in the manual mode (lens iris switch set to M). Open
the iris for better exposure.
2) In combinational use with the manual iris lens or microscope, a full-black screen image is provided from
the CCD image sensor during adjustment. When picturing after adjustment, a white screen image appears
momentarily. This phenomenon is not a symptom of trouble, however.
3) In case that the manual iris lens is used, do not attempt auto black balance adjustment while taking an
image of subject having extremely high luminance such as the sun. This may deteriorate black balance
accuracy.
2. If black balance adjustment cannot be made, any one of the following messages will appear. Take a proper procedure
according to the error message, and then try black balance adjustment again.
Error message
Procedure
AUTO BLACK:NG
CHANGE TO CAM
TRY AGAIN
•
Turn off the color bar.
AUTO BLACK:NG
IRIS NOT CLOSE
TRY AGAIN
•
Close the lens iris.
•
Avoid taking an image of subject having high luminance such as the sun, or decrease
illumination on the microscope.
AUTO BLACK:NG
???
TRY AGAIN
•
Carry out ABB again. If this message appears in repeated attempts, it is necessary to
inspect the inside of the camera. In this case, notify your local Hitachi Denshi sales
agent or Hitachi Denshi service office