When choosing a camera, you can often see markings that indicate the presence of optical or digital zoom. Despite the fact that the purpose of this technology is the same, the principle of operation and the quality at the output of the two types of image enlargement is radically different.
The term zoom comes from the English verb zoom, which literally means "to enlarge the image." When choosing a camera, many are guided by the number of pixels of the matrix, although this indicator is not the main one. Like decades ago, the dominant factor in image quality is still optics.
Optical zoom
Optical zoom is a way to bring an object closer with a lens system, which is why it is called that. Optical zoom in photographic equipment has existed for more than half a century, and the high-quality effect of image enlargement is achieved using a special device called a zoom, which is a complex optical system with the ability to change focus using multiple lenses. Magnifying the subject by means of a zoom lens helps to obtain a picture at the exit without loss of quality. There are two types of zoom: with manual mechanical focusing or with automatic focus adjustment, which is convenient for amateur photography, but is useless when creating a professional picture, for example, in macro mode. Autofocus does not provide for high sharpness at multiple optical zooming of the photographed object. In short, in cameras with automatic focusing, as a rule, the magnification is no more than threefold, while when using a mechanical zoom, an object can be brought closer to more than ten times. The most common disadvantage of cameras with manual focus and zoom (optical zoom) is the risk of dust getting inside the lens.
When choosing photographic equipment with digital zoom, a middle ground is needed between the number of megapixels of the matrix and the zoom of the zoom lens, because even with zero and five times zoom, the image is fixed at the same number of megapixels.
Digital zoom
The definition of digital zoom came along with the proliferation of compact digital cameras, which were popularly nicknamed "point-and-shoot cameras." The digital zoom is not connected with the approach of the object, since the picture displayed on the display is only stretched using the camera's matrix, being a method of framing with a significant loss of quality.
In advertising for cameras or gadgets with a camera, you can often find mention of three or five times digital zoom. It’s a paradox, but this function is most often useless, since the 5x digital zoom reduces the sharpness by several times.
With digital zoom, the picture loses its sharpness, since focusing in this case is simply absent, because focusing and focusing can only be done if the camera has an additional optical system. As a rule, the use of digital zoom is justified to enlarge the subject by no more than 40-50%, because with a higher zoom, the clarity of the picture will be very low.
