Patent ID: 6016229
Filing Date: 2000-01-18
Classification: G02B

Abstract:
A wide-angle lens system having an object side and an image side, comprising in this order from the object side:a first lens group G1 having a negative refractive power, the first lens group G1 including a positive meniscus lens and at least one negative meniscus lens in this order from the object side;a second lens group G2 having a positive refractive power;a diaphragm; anda third lens group G3 having a positive refractive power, the third lens group G3 including a cemented lens having a convex surface facing the object side, said convex surface being positioned closest to the object in this lens group, the wide-angle lens system satisfying the conditions0.5<.vertline.f1/f.vertline.<1.051.7<bf/f<4.0where f1 is a focal length of the first lens group G1, f is a focal length of the wide-angle lens, and bf is back focus.