Most cameras usually have both zooms. One is a mechanical optical tool, while the other acts on the pixels
The zoom is a fundamental element of every camera. Its main function is to increase the size of the framed image and to enlarge the field of view. But in the last case the optical device doesn't enlarge objects, but it shrinks them.
Generally, therefore, through a mechanical or digital movement (as we'll see later) the zoom allows to immortalize near or far scenes. There are several elements that differentiate one zoom from another. In particular, the most important aspect is the ability of the optical instrument to enlarge the image. This characteristic is generally indicated by numbers. So, if on the zoom is reported 5x it means that the device is able to enlarge the framed object for five times, if the value is 4x it means that it can increase the subject of four times. Zooms are present not only on cameras, but also on many other optical devices.
Optical Zoom and Digital Zoom
There are two types of zoom: optical zoom and digital zoom. Most cameras usually have both. In these cases, the function of the digital zoom is to act as a support tool for the optical zoom. There are several elements that differentiate the two zoom technologies. Leaving aside the technical aspects, the most important distinguishing feature revolves around the way in which the two zooms magnify the image.
The optical zoom, as you can also guess from its name, is composed of a set of lenses. It is, therefore, a mechanical object that moves, even automatically, back and forth. Through this movement along the axis of lenses, the zoom increases or decreases the focal length (expressed in millimeters). By doing so, the lens enlarges the framed elements, narrowing the field of view or, vice versa, increases the "immortalized" area, reducing the size of the objects.
The digital zoom, however, is different. It does not use any optical lens, but a software. The enlargement of the image, in fact, is not entrusted to a mechanical object - as the optical zoom is - but is done digitally. This means that the optical zoom acts on the pixels, which are enlarged. A bit like when you increase the size of a computer image. It is clear, therefore, that the result is not at all comparable to that obtained with the optical zoom. The photos, in fact, are generally of very low resolution.