Sony SAL35F14G Service Manual page 52

4-3-1. Optical Axis Check
1) Attach the checking lens to the flange back tester, and set the 1000 mm collimator.
1000 mm collimator
2) Set the focus ring of the checking lens to infinity end position while looking through the microscope, and align the optical axis to the
center of the chart image accurately.
3) Turn the focusing knob of the tester until the chart image is the sharpest.
Also check the optical axis aligns with the chart center. (Refer to Fig. 4-3-4.)
Note:
Figure shows example. The cause depends on individual lens.
Optical Alignment
Best alignment
4) Perform Step (1) through Step (6) and ensure that the AS and CB values are within specifications.
Note:
If the specification is "CB" only, steps (1) to (3) are not required.
AS (Astigmatism)
The phenomenon where the flare on the ring chart appears in a cruciform shape with the ring chart in the sharpest focus. (Fig. 4-3-5
(a))
(1) Turn the focusing knob until the flare becomes minimum between two approximately opposite points on the ring chart edge
(as shown with the arrows in Fig. 4-3-5 (b)), and then read the dial gauge value. <A>
(2) Turn the focusing knob until the flare becomes minimum between two points with the phase of the flare rotated by 90 degrees
from the above condition (as shown with two arrows in Fig. 4-3-5 (c)), and then read the dial gauge value. <B>
(3) Calculate the AS value (absolute difference between <A> and <B>) and ensure that it is within specifications.
AS value = <A> - <B>
CB (Center Blur)
The phenomenon where the flare on the ring chart trails in one direction with the ring chart in the sharpest focus. (Fig. 4-3-5 (d))
(4) Turn the focusing knob until the ring chart edge in the direction of the maximum flare is in the sharpest focus (as shown with
the arrow in Fig. 4-3-5 (e)), and then read the dial gauge value. <C>
(5) Turn the focusing knob until the ring chart edge, opposite 180 degrees from the above condition (as shown with the arrow in
Fig. 4-3-5 (f)) is in focus, and then read the dial gauge value. <D>
(6) Calculate the CB value (absolute difference between <C> and <D>) and ensure that it is within specifications.
CB value = <C> - <D>
SAL35F14G (1.4/35G) (35mm F1.4G)
Checking lens
Fig. 4-3-3
Incorrect aligned
e.g. As the focusing knob is turned, the chart may appear blurry as illustrated.
The cause depends on individual lens.
Fig. 4-3-4
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