Patent ID: 10191254

Abstract:
A wide-angle lens includes a first lens group, an aperture stop, a second lens group, and a third lens group. The first lens group has positive refractive power. The second lens group has negative refractive power. The third lens group has positive refractive power. The first lens group, the aperture stop, the second lens group, and the third lens group are disposed in order from the object side toward image side. The first lens group includes a negative lens and at least one cemented lens, the negative lens being disposed on most-object side and has a convex surface facing the object side. The following conditional expression is satisfied, 0.5<f1/f<1.0  (1) where f1 is a focal distance of the first lens group in a condition that infinite is in focus, and f is a focal distance of a whole system in the condition that the infinite is in focus.