PR-655/670 User Manual
70
U
SING AN
O
BJECTIVE
L
ENSES
Aligning and focusing the Optical System (Both PR-655 and PR-670)
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 diopter adjustment on 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 diopter adjustment to focus on the target.
FIGURE 65 - PR-655 / PR-670 FOCUSING
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. charact
er ‘1’ in
Correct
Incorrect
FIGURE 66 - APERTURE ALIGNMENT
Diopter
adjustment
Objective Lens
