PROBLEM TO BE SOLVED: To provide a high-performance standard zoom lens capable of ensuring an appropriate back focus while reducing the weight of a focus group, and an image pickup apparatus provided with the zoom lens.
[0003] By the way, as an autofocus mechanism of an image pickup apparatus, a phase difference method and a contrast method are known. In the phase difference method, the distance to the subject is measured by the phase difference sensor and focused. On the other hand, in the contrast method, the position where the contrast of the subject is highest is detected while moving the focus group, and that position is set as the in-focus point.
[0005] On the other hand, Patent Document 2 proposes a standard zoom lens suitable for an image pickup lens that employs a contrast-type autofocus mechanism. The zoom lens has a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a third lens group having a negative refractive power in order from the object side. It is composed of four lens groups, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power, and the fourth lens group is moved to the image side to focus on the subject.
[0006] Conventionally, a phase difference type autofocus mechanism has been widely adopted in an image pickup device to which an interchangeable lens system requiring a relatively long back focus such as a single-lens reflex camera is applied. On the other hand, the contrast type autofocus mechanism is widely adopted in an image pickup device in which the back focus is shortened by eliminating an optical viewfinder such as a mirrorless interchangeable-lens camera and a reflex mirror.
Wear. [0010] However, the zoom lens described in Patent Document 2 has a short back focus at the wide-angle end, and is difficult to apply to an interchangeable lens system such as a single-lens reflex camera that requires a relatively long back focus.
[0011] Therefore, an object of the present invention is to provide a high-performance standard zoom lens capable of ensuring an appropriate back focus while reducing the weight of the focus group, and an image pickup apparatus provided with the zoom lens. It is in.