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5-2-2. Optical Axis Check
Checking Procedure
1. Adjust the optical axis while observing the microscope until the
chart image can be seen in the center.
2. Perform steps (1) to (6) and check that the AS and CB values are
within specifications.
AS (Astigmatism):
The phenomenon where the flare on the ring chart appears in a
cruciform shape with the ring chart in the sharpest focus. (Fig. a)
(1) Turn the focusing knob until the flare becomes minimum
between two approximately opposite points on the ring
chart edge (as shown with the arrows in Fig. b), and then
(2) Turn the focusing knob until the fl are becomes minimum
between two points with the phase of the fl are rotated by 90
degrees from the above step (1) condition (as shown with
two arrows in Fig. c), and then read the dial gauge value.
and ) and check that it is within the specifi cation.
AS value = −
AS
(Fig. a)
CB (Center Blur):
The phenomenon where the flare on the ring chart trails in one
direction with the ring chart in the sharpest focus. (Fig. d)
(4) Turn the focusing knob until the ring chart edge in the direc-
tion of the maximum fl are is in the sharpest focus (as shown
with the arrow in Fig. e), and then read the dial gauge value.
(5) Turn the focusing knob until the ring chart edge, opposite
180 degrees from the above step (4) condition (as shown
with the arrow in Fig. f) is in focus, and then read the dial
gauge value.
(6) Calculate the CB value (absolute difference between
and ) and check that it is within the specifi cation.
CB value = −
CB
(Fig. d)
Specifi cation (Reference):
AS (Astigmatism)
0.06 mm or less
CB (Center Blur)
0.09 mm or less
3. If the specifications of AS and CB are not satisfied, perform the
"5-2-3. Optical Axis Adjustment (4-5 group block assy)" or the
"5-2-4. Optical Axis Adjustment (1st lens assy)".
(1)
(2)
(1)
(Fig. b)
(Fig. c)
(5)
(4)
(Fig. e)
(Fig. f)
5-2-3. Optical Axis Adjustment (4-5 group block
assy)
Note: Optical Axis Adjustment (4-5 group block assy) is done by moving
the positioning of the 5th group lens in the 4-5 group block assy.
Refer to "2-2. DISASSEMBLY", disassemble the lens, attach
the Outer Barrel for Optical Axis, and move the positioning of
the 5th group lens.
Adjustment Procedure
1. Remove the rear outer block assy and loosen the three screws to
fixing the 5th group lens, referring to the "2-2. DISASSEMBLY".
2. Attach the Outer Barrel for Optical Axis instead of the rear outer
(2)
block assy and assemble to rear shield barrel block, referring to
the "2-3. ASSEMBLY".
3. Attach the checking lens to the flange back tester referring to
the steps 1 to 3 of "Preparations of Using a Camera (General E-
mount Interchangeable Lens Digital Camera)" or "Preparations
of Using a B-L Control Box", set the 1000 mm collimator.
4. Set the zoom to the TELE end.
5. That the ring chart image becomes the center while observing
the 1000 mm collimator so insert a thin flathead screwdriver to
the hole of the lens side (three places) and moving the lens little
by little.
Look at the state of the optical axis, look at the state of the optical
axis to move again if misalignment, repeat the procedure.
Outer Barrel
for Optical Axis
(J-6082-842-A)
6. Perform the "5-2-2. Optical Axis Check", check that the optical
axis of checking lens satisfies the specification.
7. When the specification (reference value) is satisfied, tighten the
three screws loosened at step 1.
8. Remove the Outer Barrel for Optical Axis. Attach the rear outer
block assy and assemble the lens.
5-10
SEL1635GM
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