Sony SAL300F28G Service Manual ▷ View online
5-25
SAL300F28G (2.8/300 G) (300mm F2.8 G)
5-4-2.
Flange Back (f'F) Adjustment
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. Flange Back (f'F) Check].
2. Adjustment Procedure
1)
Set the focus of lens to be measured to around the infinity.
2)
Confirm the flange back value (f'F).
3)
Calculate the result obtained in steps 2) using the formula below and seek the flange back correction value.
Flange back correction value = flange back value (f'F) at the over-infinity - 46.97mm (specification((f'F)) +
0.1mm (amount of one side defocus adjustment washer)
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.
4)
Increment or decrement the washer according to the flange back correction value.
Back Adjustment Washer
Part No.
Description
Thickness (t=mm)
2-899-088-01
Ring (Back Adjustment Washer A)
4.4
2-899-088-11
Ring (Back Adjustment Washer B)
4.6
2-899-088-21
Ring (Back Adjustment Washer C)
4.8
2-899-088-31
Ring (Back Adjustment Washer D)
5.0
2-899-088-41
Ring (Back Adjustment Washer E)
5.2
2-899-088-51
Ring (Back Adjustment Washer F)
5.4
2-899-088-61
Ring (Back Adjustment Washer G)
5.6
2-899-088-71
Ring (Back Adjustment Washer H)
5.8
2-899-088-81
Ring (Back Adjustment Washer I)
6.0
2-899-088-91
Ring (Back Adjustment Washer J)
6.2
2-899-089-01
Ring (Back Adjustment Washer K)
6.4
Table 5-4-3
5-26
SAL300F28G (2.8/300 G) (300mm F2.8 G)
5)
Assemble the back adjustment washer and tighten it with four screws.
Fig.5-4-7
6)
Perform the [4. Confirmation of Flange back (f'F)] of item 5-4-1 again and confirm that the value meets the specification.
7)
If the value of flange back (f'F) does not meet the specification in the item 5-4-1, repeat the steps 1) to 6).
Rear Light Shield Barrel
Lens Mount Block
Iris Holding Tube Block
Back Adjustment Washer
5-27
SAL300F28G (2.8/300 G) (300mm F2.8 G)
5-5.
FOCUS-SHIFT CHECK/ADJUSTMENT (APERTURE (AMOUNT OF SPHERICAL
ABERRATION))
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 (SAL300F28G)
1. Preparations
1)
Perform “1. Preparations” of “5-4-1. Flange Back (f’F) Check”.
2)
Set the checking lens focus to the infinity.
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 on the tip of lens as shown in the Fig.5-5-1, then measure the flange back (f’F).
Fig.5-5-1
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).
Focus-shift = Flange back (f’F) reading (using aberration measuring cap) - flange back (f’F) of open aperture reading
Specification
Focus-shift (mm) = +0.04 to +0.18
Aberration measuring cap (SAL300F28G)
5-28
SAL300F28G (2.8/300 G) (300mm F2.8 G)
5-6.
FOCUS BRUSH (A ENCODER BRUSH) POSITION CHECK/ADJUSTMENT
Equipment
• Adhesive bond (B-10)
1. Preparation
1)
Disassemble the lens or assemble the lens to the state as shown in the figure 5-6-1.
2)
Set the focus to the
∞ (infinity) end.
Fig.5-6-1
2. Checking Adjusting Method
1)
Loosen two screws fixing the brush.
2)
Check the conduction between 1st pattern and 2nd pattern from the top with a tester.
• If the brush locates on the cut portion of
O pattern, it does not conduct. (Adjustment: OK)
• If the brush does not locates on the cut portion of
O pattern, it conducts. (Adjustment: NG)
3)
If NG in step 2), loosen two screws fixing the brush and perform step 2) again.
4)
After adjustment, apply the adhesive bond (B-10) to the heads of two screws.
Fig.5-6-2
A Encoder Brush
DV Encoder Flexible
DV Encoder Flexible
Set the focus to the infinity end
Focus Connect Ring A
Focus Connect
Ring A
Ring A
R portion of A encoder brush
Apply the adhesive bond (B-10)
A Encoder Brush
Confirm the conduction
between patterns
between patterns
DV Encoder Flexible
Cut portion
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