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5. Measurement
●
5-4 Measuring Contrast of Light
This method is useful for setting brightness levels (ratios) of key, line, hair, and eye lights
for cinematography applications or evaluating studio lighting for Photo applications. It is
also useful to check the evenness of illumination across a subject area or background
such as a green screen.
Operation
1.
Slide the Lumisphere all the way to the right
and attach the Lumidisc (optional accessory)
( ➡ P10).
2.
Turn ON just the main light source. Point the
Lumidisc toward the main light source from
the subject position and take a measurement.
3.
Next turn ON just the secondary light source. Point the Lumidisc
at the secondary light source and take a measurement.
4.
Determine the lighting
ratio (contrast ratio)
using the differrence of
measured values of the
main light source and the
secondary light source.
NOTE
● To determine exposure after adjusting lights, turn ON both main light source and
secondary light source, then take a measurement with the Lumisphere aimed in the
direction of camera's lens axis.
Lumidisc
EV Difference
of Measuring
Value
Contrast Ratio
1
2 : 1
1.5
3 : 1
2
4 : 1
3
8 : 1
4
16 : 1
5
32
:
1
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