Optical MathQuestion 95 of 100
With a 34 mm effective diameter and 4 mm per-lens decentration, what is the approximate minimum blank size?
a.About 42 mm
b.34 mm
c.30 mm
d.52 mm
Explanation
A common working rule for minimum blank size is effective diameter + (2 x per-lens decentration). 34 + (2 x 4) = 42 mm, before adding any small manufacturing tolerance.
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