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3-2. Technical description : Knee
Knee is a function to compress the luminance signal of a certain level or higher so that it can be output at a level of
about less than 109% (white clip) in order to put the brightness of an object within the Dynamic Range.
Knee Point is a setting about which level to start the compression from. It is said that the brightness of human skin is
about 85%, so professional video cameras are designed so that their settings can be set for the brightness of the
same level as human skin or higher. That is, without affecting much the gradation expression of human skin, the
gradation of brighter areas like clouds in the sky can be expressed well by using Knee.
Knee Slope indicates how much to be compressed, which means a slope of the brightness curve from Knee Point to
the maximum of Dynamic Range. Generally, when a scene includes high-brightness areas, the Knee Point is set to
a lower value to prevent blown-out highlights. On the other hand, when a scene does not include such areas, the
Knee Point is set to a higher value to prevent the gradation of middle-brightness areas from being compressed.
Adjustment Items for Knee: Main Menu > [SCENE FILE] > [KNEE SETTING] (Factory default settings underlined)
[A.KNEE RESPONSE］ 1 - - - 4 - - - 8
Sets the response speed. A smaller setting value allows a faster response speed.
(* Enabled when KNEE
MODE is AUTO)
[KNEE MASTER POINT］ 70.0% - - - 93.0% - - - 107.0%
Sets the position of Knee Point in units of 0.5%. (* Enabled when KNEE MODE is MANUAL)
[KNEE MASTER SLOPE］ 0 - - - 85 - - - 99
Sets the slope of Knee. (* Enabled when KNEE MODE is MANUAL)
[KNEE MASTER SLOPE Rch］ -31 - - - 0 - - - 31
Sets the Knee slope of Rch. (* Enabled when KNEE MODE is MANUAL)
[KNEE MASTER SLOPE Bch］ -31 - - - 0 - - - 31
Sets the Knee slope of Bch. (* Enabled when KNEE MODE is MANUAL)
This is an example for explanation only and may be different from actual measurements.
Knee Point
Knee Slope
100%
80%
90%
109%
Output Signal Level
Input Brightness Level
Knee Point: A point to start the
compression
Knee Slope: A slope of the brightness
from Knee Point to the maximum of
Dynamic Range
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