What role does the zoom lens play in the filming process?

The zoom lens can play the push-pull role in the commonly used "push-pull pan" during the filming process, that is, by changing the focal length of the lens from short to long, the subject changes from small to large (equivalent to pushing), Changing the focal length of the lens from long to short changes the subject from large to small (equivalent to stretching).

A zoom lens is a camera lens that can change the focal length within a certain range to obtain different wide and narrow angles of view, images of different sizes and different scene ranges. A zoom lens can change the shooting range by changing the focal length without changing the shooting distance, so it is very conducive to picture composition. Since one zoom lens can serve as several fixed-focus lenses, it not only reduces the amount of photographic equipment carried when traveling, but also saves the time of changing lenses.

The biggest feature of a zoom lens, or its greatest value, is that it enables the focal length of the lens to be changed according to the photographer's wishes. Different from fixed focal length zoom lenses, zoom lenses do not rely on quick lens changes to achieve lens focal length changes, but achieve lens focal length changes by pushing, pulling or rotating the zoom ring of the lens. Within the zoom range of the lens, the focal length can be changed. Level transformation means that any focal length within the zoom range can be used for photography, which creates conditions for achieving diversified compositions. Any focal length of a zoom lens itself has the same function as another fixed focal length lens of the same focal length. However, zoom lenses do not limit the photographer's use of which focal length, so they are much more convenient and flexible in use and operation. It saves you the trouble of carrying and replacing multiple lenses with different focal lengths when you go out for shooting. Even before pressing the camera shutter, the photographer can select the subject by changing the focal length of the lens and crop the picture in order to arrange the composition of the picture more ideally before shooting. The speed with which a zoom lens changes focal length is unmatched by a fixed focal length lens that changes focal length by changing lenses. The zoom lenses of 35mm automatic pocket cameras or some 35mm single-lens reflex cameras also use electric zoom mode. Electric zoom is not only labor-saving and convenient, but more importantly, it achieves even-speed zooming, which provides photographers with the advantage of different focal lengths. Subtle changes are very beneficial in cropping the picture and determining the composition. A zoom lens can also create an "explosion effect" by zooming in at the moment the camera shutter is opened. Some cameras also rely on automatic control of the focal length change of the zoom lens to achieve automatic composition. The latest 35mm single-lens reflex camera is also equipped with a function of automatically remembering the focal length of the lens. This function allows the photographer to set the camera to memorize one or several frequently used lens focal lengths, so that the lens focal length can be changed at any time. Change to the previously memorized focal length.

The role of a zoom lens:

When using a zoom lens to focus, it is best to consider focusing the image to its maximum position first; that is, use the longest focal length end of the lens focus. Then, reduce the focal length to the desired focal length when shooting. During this process, images remain sharp at all focal lengths. Using this technology, because it focuses on the largest possible image, it is easier to observe whether the image details are clear, so it is also the most accurate focusing method. Note that some zoom lenses require turning two separate control rings, one for focus and another for focus. The advantage of this structural layout is that once focusing is completed, there is no chance of accidentally changing the focus by adjusting the focus.

Other zoom lenses require only moving a control ring, turning it to focus, and sliding it back and forth to change focus. Such "single ring" zoom lenses tend to be faster and easier to operate, but are usually more expensive. Be careful not to lose sharp focus when changing focal length.