ABSTRACT
O object distance The distance from the vertex to the object. From the thin-lens equation, the image distance s for a thin-lens, whose focal length is f , can be calculated from object distance s′ as
1 s
= 1 f +
1 s′ ,
1 f
= (n′ − n)
n
( 1 R
+ 1 R′
) where the radius surface of the lens isR andR′. The object distance of a thick lens should be measured from the principal planes of the lens. See image distance.