Jadak Photo Research SpectraScan PR-7 Series, Руководство пользователя

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Chapter 8
– How to Make a Luminance / Radiance Measurement
89
Chapter - 8 H
OW TO
M
AKE A
L
UMINANCE
/ R
ADIANCE
M
EASUREMENT
If using an objective lens, the first step is to align and focus the optical system (lens and eyepiece) on the target.
FIGURE 74 - MS-75 LENS
U
SING AN
O
BJECTIVE
L
ENSES
Aligning and focusing the Optical System
1.
If using the MS-75, make sure the target is out of focus by defocusing the lens. If using a fixed focus
lens, such as the MS-2.5X, move either the target or instrument until the target is out of focus.
2.
Turn the eyepiece until the measuring aperture (black spot in the center of the field of view) is in sharp
focus. If the entire aperture does not focus simultaneously, make sure the
top and bottom of the
aperture are in focus.
3.
Focus on the target. If using the MS-75 lens, rotate the lens focusing ring until the target is in focus. If
using a fixed focus lens, move either the instrument or the target until sharp focus is achieved.
Do not
use the eyepiece adjustment to focus on the target.
4.
Make sure the measuring aperture falls within the lit area of the target. Failure to adhere to this step will
result in erroneous readings. If possible, or unless otherwise specified, we recommend that the diameter
of the aperture cover 50% to 80% of the smallest dimension of the object (e.g. character ‘1’ in Figure
75).
Grasp here to install or
uninstall lens.
Lens focusing ring