Jadak Photo Research SpectraScan PR-7 Series, User Manual

Page: 98 / 142

Chapter 9
– How to Make an Illuminance / Irradiance
Measurement
94
2
d
cd
I
=
EQUATION 5 - ILLUMINANCE FROM CANDELAS
Where: I = Illuminance in lux or footcandles.
d = Distance in feet ( footcandles ) or meters ( lux ).
Following a measurement, candelas can be calculated by:
2
* d I cd
=
EQUATION 6 - CANDELAS FROM ILLUMINANCE
U
SING THE
CR-730
FIGURE 80 - CR-730
1. From the Instrument Setup
menu, touch the ▲▼icons beneath
Primary Accessory to scroll to CR-730,
depending on the instrument being used. Make any other setup changes (exposure, sensitivity etc.) at
this time. The instrument will automatically set the
Aperture selection to the largest system configured
aperture.
2. Remove the current Primary Accessory from the instrument turning the accessory counterclockwise.
3. To Install the CR-730:
a. Loosen the thumb screw located near the mounting threads.
b. Gently separate the mounting ring from the assembly. If the mounting ring does not readily
separate, further loosen the thumb screw.
c. Install the mounting ring on the instrument by threading clockwise into the PR-7XX lens mount.
Do not over-tighten!
d. Insert the main body of the accessory into the mounting ring.
e. Rotate the receptor to the desired orientation and then tighten the thumb screw. Do not over-
tighten.