Sony SAL75300 Service Manual ▷ View online
4-12
SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
4-4.
FLANGE BACK (f’F) CHECK/ADJUSTMENT
4-4-1. Flange Back (f’F) Check
Equipment
• 1000 mm Collimator
• Flange Back Tester
• A-mount Attachment
• Flange Back Gauge (43.50mm)
1. Preparations
1)
Set the equipments as shown in the Fig.4-4-1.
Fig.4-4-1
2)
Looking through the eyepiece lens, turn the eyepiece ring of the flange back tester so that cross line or scale in the view is the sharpest.
3)
Attach the flange back gauge (43.50mm) securely to the A-mount attachment and hold them together.
4)
Turn the focusing knob of the flange back tester so that fine scratches on the flange back gauge (43.50mm) is the sharpest.
Note:
Turn the knob in the direction of the arrow of Fig.4-4-2 for correct reading.
Fig.4-4-2
5)
Turn the scale ring of the dial gauge until the long pointer indicates “0”.
Note:
This position is the flange back (f’F) = 43.50 mm.
Memorize the position of short-pointer.
flange back gauge (43.50mm)
A-mount attachment
Objective lens (10x)
Dial Gauge (Min. scale: 0.01 mm)
Scale ring
Eyepiece lens (7x)
Eyepiece ring
Focusing knob
Focus on fine lines on the surface.
Always turn the knob in the arrow
direction for correct reading.
direction for correct reading.
4-13
SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
2. Checking Method
1)
Attach the checking lens to the flange back tester, and set the 1000 mm collimator.
Fig.4-4-3
2)
Set the focus ring of the checking lens to infinity end position while looking through the microscope, and align the optical axis to the
center of the chart image accurately.
3)
Turn the focusing knob of the tester until the chart image is the sharpest (red and green color areas are equal on the chart *).
*: Position in which the color of collimator chart changes from green into red and come into focus.
Also check the optical axis aligns with the chart center. (Refer to Fig.4-4-4.)
Note:
Figure shows example. The cause depends on individual lens.
Fig.4-4-4
4)
Calculate the flange back (f’F) of the checking lens using the following formula, and check that the specification of the Table 4-4-1 is
satisfied.
Flange back (f’F) of the checking lens = (Flange back gauge) + (Number of short-pointer revolution) + (Reading of long-pointer)
Specification
Focal-length
f’F (mm)
f (mm)
(Infinity position)
75
44.60 to 44.90
100 to 200
44.50 to 44.80
300
44.60 to 44.90
Table 4-4-1
5)
When the flange back (f’F) of the checking lens is out of specification of the Table 4-4-1, perform “4-4-2. Flange Back (f’F)
Adjustment”.
Optical Alignment
Best alignment
Best alignment
Incorrect aligned
e.g. As the focusing knob is turned, the chart may appear blurry as illustrated.
The cause depends on individual lens.
e.g. As the focusing knob is turned, the chart may appear blurry as illustrated.
The cause depends on individual lens.
1000 mm collimator
Checking lens
Allowance
Appearance
Wide end
Tele end
(f = 75 mm)
(f = 300 mm)
Off center
Within 0.08 mm
Within 0.20 mm
Astigmatism
Within 0.07 mm
Within 0.14 mm
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SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
4-4-2. Flange Back (f’F) Adjustment
Equipment
• 1000 mm Collimator
• Flange Back Tester
• A-mount Attachment
• Flange Back Gauge (43.50mm)
Note:
Focus-shift adjustment must be completed before flange back (f’F) adjustment.
Adjusting Method
1)
When the focus-shift adjustment is not completed, perform “4-5. FOCUS-SHIFT CHECK/ADJUSTMENT”.
2)
Perform “4-4-1. Flange Back (f’F) Check”, and check that the flange back (f’F) of the checking lens is out of specification of the
Table 4-4-1.
3)
Calculate focus error amount using the following formula.
Focus error amount = Flange back (f’F) reading at focal length (75 mm) - 44.75 mm
Focus error amount: Amount that should be adjusted by the back washer thickness.
f’F:
Flange back value (Reading value)
4-15
SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
4)
Adjust the back washer thickness according to the result of step 3). (Refer to Table 4-4-2 and Fig.4-4-5.)
Note:
Use the micrometer gauge (or slide gauge) to measure the back washer thickness.
If focus error is a negative value: Decrease back washer thickness by error amount to increase flange back.
If focus error is a positive value:
Increase back washer thickness by error amount to decrease flange back.
5)
Calculate the adjustment washer thickness using the following formula, and replace the adjustment washer.
(Refer to Table 4-4-2 and Fig.4-4-5.)
Coupler adjustment washer thickness = Back washer thickness - 0.25 mm
Back washer
Parts No.
T (mm)
A
2-698-455-01
0.05
B
2-698-456-01
0.07
C
2-698-457-01
0.1
D
2-698-458-01
0.2
E
2-698-459-01
0.5
Coupler adjustment washer
Parts No.
T (mm)
A
2-684-057-01
0.05
B
2-684-058-01
0.07
C
2-684-059-01
0.1
D
2-684-060-01
0.2
E
2-684-061-01
0.5
Table 4-4-2
Fig.4-4-5
6)
Install the back washer and coupler adjustment washer, and perform “4-4-1. Flange Back (f’F) Check” again.
A
B
A
B
Coupler Adjustment Washer
Back Washer
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