Sony SAL75300 Service Manual ▷ View online
4-4
SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
4-2.
APERTURE DIAMETER CHECK/ADJUSTMENT
4-2-1. Aperture Diameter Check
Equipment
• Luminance Box
• Camera DSLR-A100
• AE Master Lens
• Compact Flash (CF) Card (For image saving)
• Personal Computer (PC)
(Color Calculator 2 installed)
1. Preparations
Note:
Confirm the checking lens by complete. (The adjustment of focus brush and zoom brush is completed.)
1)
Install the CF card to the camera.
2)
Set the equipments, camera and master lens as shown in Fig.4-2-1.
Fig.4-2-1
3)
Shoot the images under the following conditions and save them.
Note: Shoot the center of the luminance surface three times with the master lens and checking lens.
Setting of Luminance box:
Luminance:
EV12
Setting of Lens:
Zoom:
Wide end (focal length: 75mm)
Focus:
Infinity end
Setting of Camera:
ISO:
100
Exposure Mode:
M
shutter Speed:
1/125
Aperture:
F5.6
Focus Mode:
MF
Metering:
Center weighted
Preset white balance: Tungsten
D-R:
OFF
Luminance box
Luminance: EV12
Luminance: EV12
Camera
ISO: 100
Exposure Mode: M
Shutter Speed: 1/125
Aperture: F5.6
Focus Mode: MF
Metering: Center weighted
Preset white balance: Tungsten
D-R: OFF
ISO: 100
Exposure Mode: M
Shutter Speed: 1/125
Aperture: F5.6
Focus Mode: MF
Metering: Center weighted
Preset white balance: Tungsten
D-R: OFF
Master lens or checking lens
Zoom: Wide end (focal length: 75mm)
Focus: Infinity end
Zoom: Wide end (focal length: 75mm)
Focus: Infinity end
Shoot the center of the luminance surface
Ver. 1.2 2008.01
The changed portions from
Ver. 1.1 are shown in blue.
Ver. 1.1 are shown in blue.
4-5
SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
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2. Checking of Image
Note: Check the image of both master lens and checking lens.
1)
Start the Color Calculator 2.
Fig.4-2-2
2)
Read the image from the file menu.
Fig.4-2-3
3)
Set the Color Calculator 2 as follows.
Measured value display (Display menu): RGB+L*a*b*
Measuring method (Display menu):
Center Single Area
Fig.4-2-4
Color space (Edit menu): sRGB
Fig.4-2-5
Area size for calculate (Edit menu
→Option): 256×256 Pixels
Fig.4-2-6
4-6
SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
4)
Click the calculate button to measure the image.
5)
After measuring, check the “G” values.
Average “G” value of the three images shoot with master lens:
(a)
Average “G” value of the three images shoot with checking lens: (b)
Fig.4-2-7
3. Checking Method
1)
Calculate aperture error using the following formula, and check that the aperture error is within the specification.
Aperture error = Average “G” value of checking lens (b) - Average “G” value of master lens (a)
Specification
Aperture error = 0
±12
2)
When the aperture error is out of specification, perform “4-2-2. Aperture Diameter Adjustment”.
Calculate button
Check the “G” value
Ver. 1.2 2008.01
The changed portions from
Ver. 1.1 are shown in blue.
Ver. 1.1 are shown in blue.
4-7
SAL75300 (4.5-5.6/75-300) (75-300mm F4.5-5.6)
4-2-2. Aperture Diameter Adjustment
Equipment
Equipment
• Luminance Box
• Camera DSLR-A100
• AE Master Lens
• Compact Flash (CF) Card (For image saving)
• Personal Computer (PC)
(Color Calculator 2 installed)
• Adhesive bond (B-10)
Adjusting Method
1)
Set the checking lens into the state of Fig.4-2-8 (all exterior parts and 2nd lens set were removed).
Fig.4-2-8
2)
Temporarily attach the bayonet mount set, and set the aperture diameter to smallest opening.
3)
Set the zoom to the Wide end position (focal length: 75 mm).
4)
Loosen the three screws fixing the pressure plate.
5)
Turn the pressure plate so that the inner diameter of the diaphragm blades is 2.6 mm, and tighten the three screws.
Fig.4-2-9
2nd Lens Group
Assembly
Assembly
Screws
Screw
2.6 mm
Pressure Plate
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