To provide a large diameter telephoto lens system capable of reducing a load on an auto-focus driving mechanism by reducing the size and weight of a focus lens group and achieving excellent optical performance by satisfactorily correcting various aberrations such as a spherical aberration during focusing operation.
The large diameter telephoto lens system includes, in order from the object side; a first lens group G1 with a positive refractive power; a second lens group G2 with a negative refractive power; and a third lens group G3 with a positive refractive power. The second lens group G2 serves as a focus lens group moving in the optical axis direction during focusing from an infinite distance object to a finite distance object. The lens system satisfies the following conditional expressions (1) and (2): (1) -4<f/f2<-3 and (2) 1.3<f/f3<2.3, where f is the focal distance of the entire system, f2 is the focal distance of the second lens group, and f3 is the focal distance of the third lens group.
| JPH06138385A | 1994-05-20 | |||
| JP2012048125A | 2012-03-08 | |||
| JPH06201988A | 1994-07-22 | |||
| JPH09236742A | 1997-09-09 |
Daisuke Ando
Kuniyo Miura
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