Zoom Principles Explained: Optical Zoom, Digital Zoom, and Hybrid Zoom
Optical, digital and hybrid zoom - what is it?
In order not to get lost in the informational noise and against the backdrop of competitors, companies need loud announcements. And the best reason for a smartphone manufacturer to declare itself loudly is the release of a new model, and preferably one that has a scattering of cameras and claims to be the best camera phone. And it doesn’t matter that out of this “heap” of cameras, in fact, only one or two work. It would be nice to “spice up” all this with an impressive number of megapixels and a record zoom.
Today, manufacturers have taken it as a fashion to brag about zoom parameters as a sign that you have the “right” modern smartphone in front of you. The whole pathos of novelty in the smartphone camera comes down to who can “twist” the zoom parameters to the skies. Smartphone makers really liked to offer users the opportunity to zoom in on a frame in a few clicks without losing quality. True, a number of companies have implemented this function somehow, and also juggle the words optical, digital or hybrid zoom in the characteristics of devices, preferring not to devote potential buyers to the meaning of all these concepts.
As a result, it all turned into a fun and not very scam on the part of the manufacturers. Today, not many users understand which smartphones will offer adequate scaling, because for some this may become an important parameter when choosing a smartphone, for example, here - https://alser.kz/c/smartfony for those who live in Kazakhstan.
Optical or digital? Which is better, a smartphone with 2x optical zoom or 30x digital? The answers will be simple for you if you understand the difference and essence of various concepts.
What is camera zoom
Before diving into the intricacies of how each technology works, it’s worth understanding what zoom is. It allows you to zoom in or out on the image. Zooming in allows you to get a closer view of the object, while zooming out allows you to cover more space. This can be achieved in two ways, using optics for scaling, or programmatically cropping an area of the image and enlarging it. And the numbers in the parameters (2x, 3x, 5x) indicate how many times the camera can enlarge the object being shot.
In this case, the adjustment of the focus point is carried out only with the help of optics or lenses. They can be moved within the lens relative to each other to zoom in or out. The work of optics in this case can be compared with the work of binoculars or a telescope. The lenses scale the image, the camera “sees” the image already enlarged and captures it. In this case, there is no deterioration in image quality, and of all the methods for scaling the image, this one provides the best result.
To understand the basic principle of how optical zoom works, you need to remember two things: it's a "hardware" zoom, and the zoom itself happens before you shoot. To achieve the desired effect, a telephoto lens is used, or as it is now commonly called a periscope module. It offers one level of magnification, such as 2x, 3x or 5x.
There are quite a few models on the market today that offer optical zoom. Huawei has gone the furthest. Thus, Huawei P40 Pro + became the first flagship endowed with a camera with a 10x optical zoom, which allows you to scale objects with little loss in quality. Against its background, the same iPhone 11 Pro with its 2x optical zoom looks very modest.
Digital zoom is not zoom in the usual sense, it only creates the illusion of zoom and is a dubious option when it comes to quality zoom. In fact, this is a “software” zoom option and the zoom itself occurs after the frame is taken. It works like this. A large photo is taken from the main rear camera, the desired piece is cropped (cropped) and stretched to the entire frame size. In this case, only part of the pixel matrix is used and an effect similar to optical zoom is provided, but without the use of optics. Everything is done in software, hence the name digital zoom.
There is a cutting of the area around the selected scene in order to bring the object closer, crop it the way you want. It turns out "zoom with legs" - get close to the subject. Therefore, with digital zoom, there is a loss of quality, primarily detail and sharpness. Photos taken with digital zoom often look blurry and fuzzy. The greater the digital zoom ratio, the fewer pixels are involved in the construction of the final image, the worse the finished photo comes out. Like it or not, but the digital zoom spoils the image. Even "smart" neural networks are now unable to extend the quality of images to the level of those created through optical zoom. But the latter is not particularly favored in smartphones because of the size and high cost of telephoto lenses, as well as because of the need to make smartphones thicker, otherwise you cannot avoid the protruding module and the association that something was attached to the “back” of the gadget.
Digital zoom is used when you need to compose an image, it is not possible to get closer to the object. But such an increase has a limited use - it only makes sense when a photograph is taken with a small increase. With a large magnification of such a zoom, the image seems to break up into pixels.
Undoubtedly, zooming in many times will not offer the same sharp picture as in the original image, but it does allow you to see details that would have fallen out of sight if you had not enlarged the picture. Sometimes it is really necessary, even at the expense of quality.
It is clear that with the "hardware" option, you will get better photos with an approximation compared to the software method. But today it is not uncommon for smartphones to offer a "mix" of both types of zoom: optical and digital. Marketers have already come up with a name for this method - hybrid zoom, which provides scaling with a slight loss of quality. This is when the frame is slightly enlarged by means of an optical zoom, and then a lot of digital is added. It's better than digital zoom, but the picture quality is far from perfect.
Although the algorithms and methods used by each manufacturer may differ, the general concept is universal and corresponds to the one described above. As hybrid zoom technology evolves, chances are it could soon become a viable alternative to a periscope or telephoto camera.
Huawei began to resort to this method of scaling in its smartphones back in 2013. Now many manufacturers profess it and help the hybrid zoom with neural units (NPU), which are now part of the chips. For example, such a zoom is available in the Vivo X50 Pro, where with the help of an optical zoom you can enlarge the picture by 5 times, and with the addition of a digital one, we get an approximation of 60 times.
You can also remember the 100x zoom in the Samsung Galaxy S20 Ultra or 120x in the recently announced Xiaomi Mi 10 Ultra. This is where hybrid zoom comes into play. For example, the Samsung flagship has only a 4x optical zoom, and everything else is the work of the “hands” of the software.
The combined zoom system is used in the Oppo Reno4 Zoom. The camera system includes a lens with a focal length of 130 mm, and it provides a 2x optical zoom, and a large value of 10x is achieved through artificial image processing.
Given that users do not always see a clear line between the types of zoom, manufacturers often abuse this to flaunt numbers, while keeping silent about the zoom method that is used. So, at one time, advertising Oppo Reno 2, the company flaunted a 20x zoom, without specifying what technology was used here. And then it turned out that it was a digital 20x zoom. But the main goal of the advertisement itself was achieved. An inexperienced user has the impression that the smartphone shoots with an impressive 20x zoom.
Most experts agree that 2x, 3x optical zoom and 10x digital zoom are optimal at the moment. Everything else, when an impressive digital zoom is connected, is pampering and a guaranteed way to turn the picture into a soapy mess. Therefore, all these 50s and even more so 100s are just a marketing tool to attract attention, stand out and show “we are cooler than our competitors”.