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5-8
SAL70200G2 (2.8/70-200 G SSM Ⅱ) (70-200mm F2.8 G SSM II)
2. Projective Resolving Power Checking Method
1) Turn the focus ring of the checking lens until the chart image projected on the screen is the sharpest at the center (y = 0).
2) Read the number of the smallest pitched lines at the center (y = 0).
1) Turn the focus ring of the checking lens until the chart image projected on the screen is the sharpest at the center (y = 0).
2) Read the number of the smallest pitched lines at the center (y = 0).
The number represents for lines per mm.
Sagittal (S)
Meridional (M)
Fig.
5-4-3
3) Rotate the mount rotational plate of the lens projector while observing y = 9, y = 12, y = 15 or y = 18 and stop it at the location
where the projective resolving power is worst (low).
Read the number of the smallest pitched lines (both sagittal and meridional: 3 lines) at the peripheral point.
Note:
Note:
When reading the number of the smallest pitched lines, be careful of the spurious resolution.
Spurious resolution is the reversed image of 2 or 4 lines which appears on screen when focus is beyond maximum revolving power as shown
in Fig. 5-4-4.
in Fig. 5-4-4.
Do not confuse spurious resolution for the smallest pitched lines.
Correct resolution
Spurious resolution
Fig.
5-4-4
4) Change the focal length and projected length of the checking lens. (In case of the zoom lens), project the S image and the M image at
each focal point/projected length and confirm that the number of resolution satisfies the specification of the Table 5-4-1.
Specification
Focal length
f (mm)
Distance
(m)
Number of the smallest pitched lines (lines/mm)
Center (y = 0)
Peripheral (y = 15)
Peripheral (y = 18)
S
M
S
M
70
3.16
125 lines or
greater
63 lines or
greater
50 lines or
greater
50 lines or
greater
40 lines or
greater
135
5.7
125 lines or
greater
63 lines or
greater
32 lines or
greater
50 lines or
greater
32 lines or
greater
200
8.09
125 lines or
greater
63 lines or
greater
40 lines or
greater
50 lines or
greater
40 lines or
greater
Table
5-4-1
5) Check the projective resolving power. If the projective resolving power does not meet the specification, perform 5-4-2. Projective Re-
solving Power Adjustment (One Side Blur Adjustment) .
5-4-2. Projective Resolving Power Adjustment (One Side Blur Adjustment)
Check the projective resolving power. If it does not meet the specification, perform projective resolving power (one side blur) adjustment.
1. Adjustment procedure
1) Rotate the 1 group ball frame tube block and perform the 5-4-1.Projective Resolving Power Check .
1) Rotate the 1 group ball frame tube block and perform the 5-4-1.Projective Resolving Power Check .
In case of OK, the adjustment is finished.
If NG, perform the adjustment below.
2) Push the 5 group ball frame block in the direction of poor projection to reduce the gap.
3) Confirm the optical axis. (Refer to section 5-3-1.)
3) Confirm the optical axis. (Refer to section 5-3-1.)
In case of OK, check the projective resolving power.
If NG, perform the adjustment below.
4) Push the 1 group ball frame tube block in the direction of center shift occurrence.
In case of OK, check the projective resolving power.
5-5. FOCUS-SHIFT (FOCAL LENGTH)/FLANGE BACK (f F) CHECK/ADJUSTMENT
5-5-1. Flange Back (f F) Check
Note:
When measuring or adjusting the flange back (f F), touch the focus and the zoom as shown below.
Zoom
200
Be sure to rotate from 135 to the WIDE side and touch slowly.
70
Be sure to rotate from 100 to the TELE side and touch slowly.
Focus
Over infinity
end
end
Rotate from 3 m to the near end and touch slowly to the over infinity stopper. (Do not
slip it.)
slip it.)
Table
5-5-1
1) Set the focal length to the WIDE end (70 mm).
2) Set the focus to the over infinity end.
3) Confirm the flange back (f F) value at the WIDE end (70 mm).
4) Set the focal length to the TELE end (200 mm) and confirm the flange back (f F) value.
2) Set the focus to the over infinity end.
3) Confirm the flange back (f F) value at the WIDE end (70 mm).
4) Set the focal length to the TELE end (200 mm) and confirm the flange back (f F) value.
Flange back (f F) value =
(Value of flange back gauge for SR) + (Number of rotation of short pointer) + (Scale of long pointer)
Specification
Focal Length
f (mm)
Flange back value f F (mm)
Over infinity end
Over infinity end
Flange back value f F (mm)
Optical infinity (L index) difference from over infinity end
Optical infinity (L index) difference from over infinity end
200
46.59
±
0.07 (46.52 to 46.66)
-1.99
70
44.87
±
0.07 (44.80 to 44.94)
Table
5-5-2
5) Rotate the knob of microscope and set the dial gauge to the value below.
Flange back (f F) value at the TELE end (200 mm) and over infinity end - 1.99 (mm)
6) Rotate the mirror tube block so that it is in focus.
Confirm that the L index is in the range shown below.
Fig.
5-5-1
7) If it does not meet the specification in the steps up to 6), after implementing the 5-5-2. Focus-Shift (Focal Length) Check/Adjustment ,
perform the 5-5-3. Flange back (f F) Adjustment .
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