Sony SAL1118 Service Manual page 41

2. 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).
3) Turn the mount rotation ring of lens test projector until the projected image at a certain peripheral point (y'= 9) on the screen appears
the most unsharp.
Read the number of the smallest pitched lines (both saggital and meridional: 3 lines) at the peripheral point.
When the partial blur appears, loosen the three fixing screws of the 5th lens barrel assembly shown in the Fig.4-4-5 and adjust the
position to from side to side and up and down.
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.
Do not confuse spurious resolution for the smallest pitched lines.
Correct resolution
Fig.4-3-4
4) Change the focal-length (zoom) and distance of the checking lens, and check that the all readings (y'= 0, saggital (S) and meridional
(M) at y'= 9) at each focal-length (zoom) and distance is within the specification of the Table 4-3-2.
Specification
Focal-length f (mm)
11
12
14
16
18
SAL1118 (4.5-5.6/11-18) (DT 11-18mm F4.5-5.6)
Fig.4-3-3
Spurious resolution
distance (m) Number of the smallest pitched lines
Center (y'= 0)
(Lines per mm)
0.66 100 or greater
0.72 100 or greater
0.84 100 or greater
0/96 100 or greater
1.08 100 or greater
Table 4-3-2
The number represents for lines per mm.
Saggital (S)
Meridional (M)
Peripheral (y'= 9)
(Lines per mm)
S M
40 or greater 40 or greater
40 or greater 40 or greater
40 or greater 40 or greater
40 or greater 40 or greater
40 or greater 40 or greater
4-10