Sony SAL1680Z Service Manual page 61

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:
Average "G" value of the three images shoot with checking lens: (b)
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 master lens (a) - Average "G" value of checking lens (b)
Specification
Aperture error = –20 to +5 (Wide end: 16mm)
2) When the aperture error is out of specification, perform "4-2-2. Aperture Diameter Adjustment".
SAL1680Z (Vario-Sonnar DT 3.5-4.5/16-80 ZA) (Vario-Sonnar T
Calculate button
Fig.4-2-7
(a)
Check the "G" value
DT 16-80mm F3.5-4.5 ZA)
*
4-15