dc589da6_iew_of_Canon_s_pro_digital_SLR__Description
[Setting] Hybrid Auto WB [Colour Temp. (Kelvin)] 4000K-7000K [Description] 
Camera sets the WB automatically and steplessly within its workin colour temperature range. It combines readings from actual image data (the portion of the photo that falls within the spot metering circle) and from the external semi-opaque sensor on the front of the camera (shown at left).
Rob Galbraith DPI: Canon EOS-1D: a preview of Canon's pro digital SLR
Description