Sony SAL20F28 Service Manual page 36

3) Move the preset lever to set the preset ring at the open aperture position.
Set the preset ring at the open aperture position.
Fig.4-2-11
4) Turn the aperture unit holding ring to adjust the position that the aperture blades are hidden into the edge completely.
Aperture Unit Holding RIng
5) After the adjustment is completed, apply the adhesive bond (B-10) as shown in the Fig.4-2-13.
6) Assemble the lens completely.
7) Perform "4-2-1. Aperture Diameter Check", and repeat "4-2-1. Aperture Diameter Check" and "4-2-2. Aperture Diameter Adjust-
ment" until the aperture error is within the specification.
SAL20F28 (2.0/28) (20mm F2.8)
Preset lever
Aperture blades are hidden into
the edge competely.
Fig.4-2-12
Apply adhesive bond(B-10)(3 areas)
Aperture Unit
Bond Holding Ring
Aperture Unit
Holding Spring
Fig.4-2-13
4-8
Bond