Focus-Shift Check/Adjustment; Spherical Aberration)) - Sony SAL1680Z Service Manual

Ver. 1.2 2007.08
The changed portions from
Ver. 1.1 are shown in blue.
4-7. FOCUS-SHIFT CHECK/ADJUSTMENT (APERTURE (AMOUNT OF SPHERICAL
ABERRATION))
This section describes the check/adjustment 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 62mm (SAL1680Z)
1. Preparations
1) Perform "1. Preparations" of "4-4-1. Flange Back (f'F) Check".
2) Set the checking lens focus to the infinite.
3) Set the focal length 80mm.
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 62mm on the tip of lens as shown in the Fig.4-7-1, then measure the flange back (f'F).
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 62mm).
Focus-shift = Flange back (f'F) reading (using aberration measuring cap 62mm) - flange back (f'F) of open aperture reading
Specification
Focus-shift (mm) = – 0.12 to +0.09
4) Perform the "4-12. WRITE dSB".
SAL1680Z (Vario-Sonnar DT 3.5-4.5/16-80 ZA) (Vario-Sonnar T
Aberration measuring cap 62mm (SAL1680Z)
Fig.4-7-1
DT 16-80mm F3.5-4.5 ZA)
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4-29