US Patent 7110188 Small imaging lens and imaging apparatus

An imaging lens includes sequentially, from an object side, a first lens group, a second lens group, a third lens group, and a fourth lens group. The first lens group includes only a first lens having a meniscus shape with a concave surface facing the object side. The second lens group has positive refracting power as a whole and includes sequentially, from the object side, a second-first lens having positive refracting power and a second-second lens cemented to or separated from the second-first lens and having negative refracting power. The third lens group includes only a third lens having a meniscus shape with a concave surface facing the object side. The fourth lens group includes only a fourth lens.