| 摘要 |
A variable focal length lens system having, in the order from the object side, a first positive lens unit, a second positive lens unit and a third negative lens unit. In order to vary the focal length from the wide position to the tele position, the first positive lens unit and the third negative lens unit are moved jointly or independently toward the object side while the second positive lens unit is moved toward the object side at a lower speed than the first and third lens units. The variable focal length lens system satisfies the following conditions: 0.5<¦f3/fW¦<0.9 (1) 1.3< beta 3W<2.0 (2) 0.5<f2/fW<1.3 (3) where fW is the focal length of the entire system at the wide position, f2 and f3 are the focal lengths of the second and third lens units, respectively, and beta 3W is the image magnification of the third lens unit at the wide position.
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