Read Sony SAL100M28 Service Manual online
4-14
SAL100M28 (MACRO 2.8/100) (100mm F2.8 Macro)
4-5.
FOCUS-SHIFT CHECK
This section describes the check of focus-shift amount resulting change of focal-length by aperture setting.
Equipment
• 1000 mm Collimator
• Flange Back Tester
• A-mount Attachment
• Flange Back Gauge (43.50mm)
• Aberration Measuring Cap 55mm
1. Preparations
1)
Perform “1. Preparations” of “4-4-1. Flange Back (f’F) Check”.
2. Checking Method
1)
Set the lens aperture to the open aperture position, and measure the flange back (f’F).
2)
Set the aberration measuring cap 55mm (F8 equivalent) on the tip of lens as shown in the Fig.4-5-1, then measure the flange back
(f’F).
Fig.4-5-1
3)
Calculate amount of focus-shift using the following formula, and check that the specification is satisfied.
Note:
The focus-shift amount of the checking lens is difference between the flange back (f’F) of open aperture and flange back
(f’F) reading (using aberration measuring cap 55mm).
Focus-shift = flange back (f’F) reading (using aberration measuring cap 55mm) - flange back (f’F) of open aperture reading
Specification
Focus-shift (mm) =
0
to +0.08
4)
When the focus-shift is out of specification, perform the parts replacement and adjustment/check referring to the Fig.4-5-2.
Fig.4-5-2
Aberration measuring cap 55mm
4-4. FLANGE BACK (f'F)
CHECK/ADJUSTMENT
END
4-4. FLANGE BACK (f'F)
CHECK/ADJUSTMENT
END
4-4. FLANGE BACK (f'F)
4-5. FOCUS-SHIFT CHECK
CHECK/ADJUSTMENT
OK
END
Replace the BLOCK (LEAD FREE),
3 GROUP LENS (A-1192-253-A)
4-5. FOCUS-SHIFT CHECK
OK
NG
Replace the G6 LENS
(2-685-634-01)
4-5. FOCUS-SHIFT CHECK
OK
Replace the BLOCK (LEAD FREE),
FRAME LENS (A-1192-239-A)
NG
Ver. 1.4 2008.05
The changed portions from
Ver. 1.3 are shown in blue.
Ver. 1.3 are shown in blue.
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