GRASS VALLEY Focus 70 Live, User Manual

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58 Focus 70 Live Highly Affordable HD System Camera User’s Guide (v1.1)
Chapter 5 - Video setup
5.3 Gamma
5.3.1 Gamma correction
To compensate for the non-linear response of display devices, a gamma correction is applied to
the video signal. The gamma correction adjusts the tonal response of the standard transfer
curve.
5.3.2 Gamma curve
The gamma curve defines the distribution of tonal values. The following standard gamma
curves are available: BBC04, BBC05 and BBC06, ARD, ITU709 (default), RAI, Gamma-J and
Gamma-S.
Press the GAMMA button and select
GAMMA CRV
to select the gamma curve you want to use.
In the camera menu, navigate to the
PRODUCTION SETUP > LEVELS > GAMMA > CURVE
item
and select the gamma curve you want to use.
5.3.3 Gamma presets
The gamma preset selection determines how mid-range tonal values are reproduced. Available
gamma presets are:
• Nom (nominal) setting: Master Gamma = 76 (slope = 0.45)
• Lin (linear) setting: Master Gamma = 0 (slope = 1.00)
• Var (variable) setting: Master Gamma is adjustable between 0 (slope = 1.00) and 99 (slope
= 0.35).
Press the GAMMA button and use the
GAMMA SEL
item to select the Gamma preset.
In the camera menu, navigate to the
PRODUCTION SETUP > LEVELS > GAMMA > PRESET
function and select the Gamma preset from the list.
☞
Note
☞
Note
It’s also possible to change Gamma for each channel (R,G,B). Changing the slopes of the
individual color gamma changes the representation of white in the mid-range tonal values.
0 20 40 60 80 100
0
20
40
60
80
100
γ
= 1.00 (Master Gamma=0)
γ
= 0.35 (Master Gamma=100)
OCP
CAM
OCP
CAM