( ( ( The ( second type ) ) ( of lens ) ) ( ( is ( the ( soft lens ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ second) (NN type)) (PP (IN of) (NP (NN lens)))) (VP (VBZ is) (NP (DT the) (JJ soft) (NN lens))) (. .)))
The second type of lens is the soft lens .
(ROOT (S (NP (DT A) (JJ concave) (NN lens)) (VP (VBZ is) (NP (NP (JJR thicker)) (PP (IN at) (NP (DT the) (NNS edges)))) (SBAR (IN than) (S (NP (PRP it)) (VP (VBZ is) (PP (IN in) (NP (DT the) (NN middle))))))) (. .)))
A concave lens is thicker at the edges than it is in the middle.