Sony SAL1118 Service Manual page 47

4-4-3. Focus-shift Adjustment
This section describes the check/adjustment of focus-shift amount resulting change of the focal-length by zooming.
Equipment
• 1000 mm Collimator
• Flange Back Tester
• A-mount Attachment
• Flange Back Gauge (43.50mm)
Adjusting Method
Note:
About the insulating tape in the sentence. When shipping it, Mending tape (2-886-794-01) is used.
1) Perform "4-4-1. Focus-shift/Flange Back (f'F) Check and Optical Axis Adjustment", and check that the flange back (f'F) of the
checking lens is out of specification of Table 4-4-1.
2) Set the zoom ring of the checking lens to Wide end position (focal length: 11 mm).
3) Set the support barrel assembly of the checking lens to infinity position (center of the "L" mark index). (Fig. 4-4-6)
4) Turn the knob of the flange back tester until the chart image is the sharpest while looking through the microscope, and check the
flange back (f'F).
5) Set the zoom ring of the checking lens to Tele end position (focal length: 18 mm).
6) Peel off the two insulating tapes. (Fig 4-4-6)
7) Turn the support barrel assembly until the chart image is the sharpest.
8) Set the focus gear barrel to the infinity position (infinity end) while maintaining the support barrel assembly so as not to rotate it.
Affix the two insulating tapes. (Fig 4-4-6)
9) Perform steps 2) to 8) until the specification of focus-shift amount (difference between the maximum flange back (f'F) and minimum
flange back (f'F)) of the checking lens is met.
Focus-shift = Maximum flange back (f'F) reading - Minimum flange back (f'F) reading
Specification
Focus-shift: Less or equal 0.03 mm
1.5 2 3 10
3
0.5 0.7 1
Align the center
SAL1118 (4.5-5.6/11-18) (DT 11-18mm F4.5-5.6)
∞ ft
m
Fig4-4-6
Support barrel assembly
L mark index
Index
4-16
Insulating Tape (Two areas)
Focus gear barrel