Sony SAL70200G (serv.man2) Service Manual ▷ View online
5-27
SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
4. Flange Back (f'F) Check
Note:
Note:
When measuring or adjusting the flange back (f'F), touch the focus and the zoom as shown below.
Zoom
200
Be sure to rotate from “135” to the WIDE side and touch slowly.
70
Be sure to rotate from “100” to the TELE side and touch slowly.
Focus
∞
Rotate from 3m to the near end and touch slowly to the over infinity stopper. (Do not slip it.)
1)
Set the focal length of lens to be measured to the WIDE end “70mm”.
2)
Set the focus of lens to be measured to the infinity end.
3)
Confirm the flange back (f'F) value at the focal length WIDE end “70 mm”.
4)
Set the focal length to the TELE end “200mm” and confirm the flange back (f'F) value.
Flange back (f'F) value of checking lens =
(Value of flange back gauge for SR) + (Number of rotation of short pointer) + (Scale of long pointer).
Specification
Focal Length f(mm)
Flange back value (mm)
Flange back value f'F(mm)
Over infinity (Touching to the infinity side)
Optical infinity (L index)
Difference from over infinity
Difference from over infinity
200
46.59
± 0.07 (46.52 to 46.66)
-1.99
70
44.87
± 0.07 (44.80 to 44.94)
Table 5-4-2
5)
Rotate the knob of microscope and set the dial gauge to the value below.
Flange back (f'F) value at the focal length TELE end “200mm” over infinity - 1.99 (mm)
6)
Rotate the mirror tube block so that it is in focus.
Confirm that L index is in the range shown below.
Fig.5-4-9
7)
If not met the specification in the steps up to 6), after implementing the “5-4-2. Focus-Shift (Focal Length) Check/Adjustment”,
perform the “5-4-3. Flange back (f'F) Adjustment”.
5-28
SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
5-4-2. Focus-Shift (Focal Length) Check/Adjustment
In this section, the procedure to adjust the focus change occurred when changing the focal length is described.
Equipment
• 1000mm collimator
• Flange back measuring equipment
• A-mount attachment
• Flange back gauge (43.50mm)
1. Preparation
Perform the “1. Preparation” of “5-4-1. Optical Axis Check/Adjustment and Flange back (f'F) Check”.
2. Check/Adjustment Procedure
1)
Set the focal length of lens to be measured to the TELE end “200mm”.
2)
Set the focus of lens to be measured to the infinity end.
3)
Set to the focal length to the TELE end “200mm” and confirm the flange back (f'F) value.
4)
Set to the focal length to the WIDE end “70mm” and confirm the flange back (f'F) value.
5)
Calculate the results obtained in steps 3) and 4) using the formula below and determine the amount of focus point movement
adjustment washer.
Amount of focus point movement adjustment washer (mm) =
{
(46.59 - (Tele end f'F)
)
- (44.87 - (Wide end f'F)
)}
/ - 0.86
When the amount of focus point movement adjustment washer is positive value (+):
Make the focus point movement adjustment washer thicker.
When the amount of focus point movement adjustment washer is negative value (-):
Make the focus point movement adjustment washer thinner.
Specification
Focal Length f(mm)
Focus-shift (mm)
70 to less than 135
-0.1 to +0.1
135 to 200
-0.15 to +0.1
Table 5-4-3
6)
Corresponding to the result of focus point movement adjustment washer amount, increase or decrease the focus point movement
adjustment washer.
Focus Point Movement Adjustment Washer
Part No.
Description
thickness(mm)
2-691-553-01
Focus Point Movement Adjustment Washer A
0.05
2-691-554-01
Focus Point Movement Adjustment Washer B
0.07
2-691-555-01
Focus Point Movement Adjustment Washer C
0.1
2-691-556-01
Focus Point Movement Adjustment Washer D
0.2
2-691-557-01
Focus Point Movement Adjustment Washer E
0.5
Table 5-4-4
Ver. 1.5 2010.01
The changed portions from
Ver. 1.4 are shown in blue.
Ver. 1.4 are shown in blue.
5-29
SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
7)
Set the lens unit as shown in the Fig. 5-4-10 and assemble the focus point movement adjustment washer.
Fig.5-4-10
Focus Point Movement Adjustment Washer
5-30
SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
5-4-3. Flange Back (f'F) Adjustment
Equipment
• 1000mm collimator
• Flange back measuring equipment
• A-mount attachment
• Flange back gauge (43.50mm)
Note:
Perform the flange back (f'F) adjustment after competing the “5-4-2. Focus-Shift (Focal Length) Check/Adjustment”.
1. Preparation
Perform the “1. Preparation” of “5-4-1. Optical Axis Check/Adjustment and Flange back (f'F) Check”.
2. Adjustment Procedure
1)
Set the focal length of lens to be measured to the WIDE end “70mm”.
2)
Set the focus of lens to the infinity.
3)
Confirm the flange back value (f'F) at the focal length WIDE end “70mm”.
4)
Calculate the results obtained in steps 3) using the formula below and seek the flange back correction value.
Flange back correction value (mm) = flange back value (f'F) at the focal length Wide end “70mm” Over infinity - 44.87 mm
When the flange back correction value is positive (+): Make the back adjustment washer thicker.
When the flange back correction value is negative (-): Make the back adjustment washer thinner.
Back Adjustment Washer
Part No.
Description
thickness(mm)
2-691-806-01
Back Adjustment Washer A
0.05
2-691-807-01
Back Adjustment Washer B
0.07
2-691-808-01
Back Adjustment Washer C
0.10
2-691-809-01
Back Adjustment Washer D
0.20
2-691-810-01
Back Adjustment Washer E
0.50
Table 5-4-5
6)
Assemble the back adjustment washer and perform the “4. Flange back (f'F) Check” of section 5-4-1 again and confirm that the value
meets the specification.
Fig.5-4-11
Lean the outer tube block and
insert the back adjustment washer
as shown in figure.
insert the back adjustment washer
as shown in figure.
Back Adjustment Washer
Loosen the four screws
Outer Tubu Block
Connect Barrel Unit
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