Patent attributes
The variable-power optical system is provided and includes a first lens group having a negative refractive power, a stop, and a second lens group having a positive refractive power, in order from an object side. The first lens group includes a first sub lens group having three negative meniscus lenses and a second sub lens group having a biconcave lens and a positive lens, in order from the object side. The second lens group includes a first positive lens arranged closest to the object side and having at least one aspheric surface and a second positive lens arranged immediately after the image side of the first positive lens. When the absolute value of the focal length of the first lens group is |f1| and the focal length of the entire system at a wide angle end is fw, the Conditional expression: 1.9<|f1|/fw<3.6 is satisfied.
