Operation Manual

11
2.Lumidisc
Employ for illumination contrast adjustment and illuminance measure-
ment.
6. STANDARD ACCESSORY OPERATION
Main light
Fill-in light
•
Contrast measurement
a. Mount Lumidisc @3 to light
sensor w. Install in the same
manner as Lumisphere. (See
P. 8)
b. Hold meter at subject position
and point Lumidisc @3 directly
toward center of main light.
c. Press stopper button !3 and
read meter scale footcandle
indication e.
d. Turn the memo pointer dial
and set the memo pointer !7
at the footcandle value the
needle points to.
e. In the same manner, measure
the fill-in light. In this case,
take care that light from main
source does not enter sensor.
f. Read a difference between
the footcandle value the
memo pointer is set (see
above d) and the one for fill-
in light (= needle position).
Ratio between main and fill-in light footcandles becomes the con-
trast ratio.
Example:With main light at 640 footcandles, fill-in light reads 320 foot-
candles. Illumination contrast ratio becomes;
640 2
320 1
or 2 : 1
=