Grass Valley TTV 1657D - Manuel (Page 123)

Chapter 2 - Camera 123
Description
THOMSON TTV 1657D
User manual
B1657D902C
Septembre 2000
4 - Lens attaching ring
5 - "WHT BLK" selector switch
Three-position automatic return to centre position selector switch:
• setting the selector switch to WHT starts white balance automatic adjustment,
• setting of the selector to BLK starts automatic adjustment of the black pulses and black
balance. Holding on BLK (for more than 3 sec.) starts the black shading automatic
adjustment cycle.
White automatic balance (or RGB level white balance):
• Purpose: this automatic device compensates for RGB video level errors due to changes
in scene lighting.
• Remarks:
1) The white automatic balance equalises the RGB levels of the most luminous object
located in the centre area of the image. Consequently, pay attention to the following
points:
- place the white reference in the centre of the image,
- make sure that no luminous object is located in this central area.
2) Select white balance memory A or B.
3) Run a white balance before each shooting session and on each lighting colour
temperature change.
The corrections are conserved when the equipment is switched off.
• NOTES:
1) The camera features a "permanent white balance" mode in which balancing is
performed permanently. To activate this mode, press the selector towards "WHT" a
second time before the end of the automatic balance cycle ("W" is displayed in
viewfinder). To quit this mode, select "WHT" again.
2) In "ENG", the camera is forced to the auto iris mode during the balancing time
(except in the permanent balance mode).
Black automatic balance (or RGB level black balancing):
• Purpose: this automatic device equalises the RGB black levels and adjusts the black
pulses to maintain the black at a constant level whatever the camera gain.
• Remarks:
1) Run a black automatic balance on the first shooting session of the day.
2) The automatic device closes the iris during adjustment time. Consequently, if the
iris switch on the lens were in the MAN position, the lens will remain closed at the
end of the adjustment.