What does zoom lens mean?

The lens enlarges from far to near, which is called zoom lens;

Zoom lens is a kind of camera lens that can change the focal length in a certain range, so as to get different field of view, different images and different scene ranges. Zoom lens can change the shooting range by changing the focal length without changing the shooting distance, so it is very beneficial to picture composition. Because a zoom lens can also serve as several fixed-focus lenses, it not only reduces the number of photographic equipment to carry when traveling, but also saves the time for changing lenses.

Extended data:

When using zoom lens to focus, it is best to adjust the image to the maximum position first; In other words, the longest focal length end of the lens is used for focusing. Then, reduce the focal length to the desired focal length when shooting.

In this process, the images of all focal lengths are always clear. Using this technology, it is easier to observe whether the image details are clear because it focuses on the image as large as possible, so it is also the most accurate focusing method. Note that some zoom lenses need to rotate two independent control rings, one ring controls the focal length and the other ring controls the focal length. The advantage of this structural layout is that once the focus is completed, the focus will not be unexpectedly changed by adjusting the focus.

Other zoom lenses only need to move a control ring, turn to focus, and slide back and forth to change the focal length. This kind of "single ring" zoom lens is often faster and easier to operate, but it is usually more expensive. When changing the focal length, be careful not to lose the clear focus.