46
6-4. Contrast Function
This function is useful for evaluating studio lighting, checking evenness of backgrounds
such as green screens, and quick set up of lighting ratios.
After establishing a standard value, press and hold the Measuring button
8
to display the
difference between the standard and new measured value. The exposure value will change
to an EV value (difference in stops) change as brightness of the measured value changes.
The Analog Scale will display the current measured value.
* If no values are in memory, the standard value will be the last value measured. If values
are in memory, the standard value will be the average of all memorized values.
Creating Lighting ratios with Contrast Function (in Shutter Speed Priority Mode in incident light):
Retract the Lumisphere when making contrast readings.
1. Rotate the Lumisphere retracting ring
2
until
fully switching to the flat position.
2. Switch ON the main light source and point the
retracted lumisphere at the light source from
the subject position.
3. Touch the Average/
D
EV icon
at the
bottom of the screen to use the current reading
(or memorized value) as “Standard Value" and
display AVE on the measuring screen. The
Average/
D
EV icon
will appear in reverse
as long as it is the Contrast Function is active.
4.
Next turn ON a second light source (fill light,
hair light, etc.). Point the retracted lumisphere
at the source from the subject position and
press the Measuring button
8
. The display will
change from exposure setting to EV value and
indicate the difference in brightness between
the Standard and the second value being
measured. The analog scale will also display the
two values. The table below shows the lighting
ratio according to the difference in brightness.
EV Difference of Measuring Value
Illumination Ratio
1
2:1
1.5
3:1
2
4:1
3
8:1
4
16:1
5. To return to normal measuring, touch the Average/
D
EV icon
again.
•
To determine the final exposure after setting the lighting ratio, extend the lumisphere, switch ON all lights, and point
the Lumisphere back towards the camera from the subject position and press the measuring button.
•
The Contrast Function also can be used when measuring with reflected light.
Lumisphere retracting ring
2
Ave
Setting
value
Touch AVE/
D
EVicon
Release the
Measuring button
Example of Main Light
Source Measuring
Measuring value
using main light source
Last measuring Value
Standard
Value
Example of while contrast
function is active
Standard value
(main light source)
Monitored value
(second light
source) during measuring