Sony SAL70200G (serv.man2) Service Manual ▷ View online
5-23
SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
5-4.
OPTICAL AXIS/FOCUS-SHIFT (FOCAL LENGTH)/FLANGE BACK (f’F) CHECK/
ADJUSTMENT
ADJUSTMENT
5-4-1. Optical Axis Check/Adjustment and 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.5-4-1.
Fig.5-4-1
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.5-4-2 for correct reading.
Fig.5-4-2
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.
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SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
2. Optical Axis Check
1)
Attach the checking lens to the flange back tester, and set the 1000 mm collimator.
Fig.5-4-3
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.5-4-4.)
Note:
Figure shows example. The cause depends on individual lens.
Fig.5-4-4
4) Check that the specification of the Table 5-4-1 is satisfied.
CB
Phenomenon that seems that color (flared) remains in one direction of ring chart at the best focus.
AS
Phenomenon that seems that color of ring chart divides into direction of cross at the best focus.
Fig.5-4-5
Specification
WIDE End
TELE End
CB
0.07mm or less
0.1mm or less
AS
0.07mm or less
0.07mm or less
Table.5-4-1
5) When the CB and AS of the checking lens is out of specification of the Table 5-4-1, perform the “3. Optical Axis Adjustment”.
When the specification is meet, perform “4. Flange Back (f’F) Check”
1000 mm collimator
Checking lens
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.
CB
AS
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SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
3. Optical Axis Adjustment
1)
Push the 1 group ball frame tube block to reduce the gap or play.
a.
While observing the collimator, confirm the direction where the CB occurs.
b.
Push the 1 group ball frame tube block in the direction of CB.
c.
Observe the collimator again and confirm the optical axis.
Fig.5-4-6
2)
If the result in step 1) does not meet the specification, push the 5 group ball frame block to reduce the gap or play.
a.
Disassemble up to outer barrel.
b.
Push the 5 group ball frame tube block in the opposite direction where the CB occurs.
Fig.5-4-7
G1 Holding Rubber
1 Group Ball Frame Tube Block
G1 Holder Ring
5 Group Ball Frame Block
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SAL70200G (2.8/70-200 G) (70-200mm F2.8 G)
3)
If the result does not meet the specification in steps 1) and 2), push the 1 group ball frame tube block to reduce the gap or play again.
4)
When the optical adjustment is completed, make the marking-off on the bore of mirror tube block and outer diameter of 1 group ball
frame tube block (G3 riveting tube block).
Note:
When making the marking-off, remove the G1 lens and the G2 lens.
Fig.5-4-8
Mirror Tube Block
G3 Riveting Tube Block
G1
G2
1 Group Ball Frame Tube Block
G1 Holder Ring
Make the marking-off on the outer diameter
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